Review Reports

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Reviewer 1 Comment

Response

1.

Abstract: Briefly discuss the adequacy of the PLS-SEM sample size, focusing on statistical power and generalizability.

Thank you for this valuable comment. The Abstract now explicitly addresses sample adequacy: the 157 valid responses exceed both the a priori statistical power requirement computed in G*Power 3.1 (n = 103 for a medium effect, f² = 0.15, with seven predictors, α = 0.05, power = 0.80) and the inverse square root criterion (n = 137). The Abstract also acknowledges that generalizability remains bounded by the purposive, single-country sample. The full power analysis is reported in the Methodology.

Location of revision: Abstract (new sentences after the description of the sample); Section 3.3, paragraph 4.

2.

Abstract: Strengthen the novelty of the proposed TOE-based framework by clearly demonstrating how it advances beyond existing 3DP studies that employ TOE or SEM approaches.

Thank you for this constructive suggestion. The closing sentences of the Abstract have been rewritten to state precisely how the study advances beyond prior TOE- and SEM-based 3DP research: it disaggregates the three TOE contexts into seven empirically validated CSF constructs, quantifies their relative influence, and delivers the first validated adoption framework of this kind for the Egyptian construction sector. These claims are substantiated in Sections 2.5 and 5.1.

Location of revision: Abstract (final sentences); Sections 2.5 and 5.1.

3.

Introduction: Please strengthen the discussion of 3DP adoption barriers in Egypt and other developing countries by supporting the claims with more recent and high-impact references.

Thank you for this helpful comment. The third paragraph of the Introduction has been substantially expanded and is now supported by recent, high-impact sources, including Besklubova et al. (J. Constr. Eng. Manag. 2021), Waqar et al. (Ain Shams Eng. J. 2024), Chang and Antwi-Afari (Constr. Innov. 2025), Shivendra et al. (Infrastructures 2024), Opawole et al. (2022), and Daoud et al. (Waste Manag. Res. 2020). The paragraph now also situates the barriers within the specific characteristics of the Egyptian market and comparable developing markets (India, Nigeria, Sri Lanka).

Location of revision: Section 1, paragraph 3 (marked in red); References [5–13].

4.

Introduction: Justify the selection of TOE framework over TAM and UTAUT for examining 3DP adoption in construction industry.

Thank you for raising this important theoretical point. A new paragraph has been added to the Introduction justifying the selection of TOE over TAM and UTAUT: TAM and UTAUT are individual-level acceptance models, whereas C3DP adoption is an organization-level decision contingent on firm resources, managerial capability, and external regulatory and market conditions, which TOE explicitly captures. The justification cites the seminal sources (Tornatzky and Fleischer, 1990; Davis, 1989; Venkatesh et al., 2003) and prior TOE applications in construction (Badi et al., 2021; Waqar et al., 2023; Wu et al., 2018). Section 2.5 was extended accordingly.

Location of revision: Section 1, new paragraph 4 (in red); Section 2.5, extended final sentences.

5.

Literature review: Enhance the critical synthesis by minimizing descriptive summaries and strengthening analytical comparisons across studies instead of listing their historical development and individual findings.

Thank you for this insightful comment. The literature review has been revised to add analytical comparison rather than description: Section 2.1 now closes with a critical observation that technological maturity has outpaced managerial, regulatory, and market readiness; Section 2.2 now contrasts the magnitude and context-dependence of reported benefits (e.g., cost-competitiveness only for complex geometries) and compares barrier severity between developed and developing markets; Section 2.3 adds a cross-country comparative analysis of implementation experiences; and Section 2.6 was restructured around three critical observations that define the research gap.

Location of revision: Sections 2.1 (final paragraph), 2.2, 2.3 (two new paragraphs), and 2.6 (all in red).

6.

Literature review: Improve citation integration by emphasizing recent, high-impact, peer-reviewed studies and reducing reliance on older sources.

Thank you for this valuable comment. The reference list has been thoroughly upgraded: recent high-impact studies were added (2018–2025, including Cem. Concr. Res., Autom. Constr., J. Constr. Eng. Manag., Constr. Innov., and Ain Shams Eng. J.), incomplete or unverifiable citations were replaced with complete peer-reviewed sources (e.g., “Motalebi & Kabir (2024)” corrected to the full systematic review by Motalebi et al.; the fragmentary “Liu & Chen (2023)” entries replaced with Buswell et al. (2018) and García de Soto et al. (2018)), and older sources were retained only where seminal (e.g., Tornatzky and Fleischer, 1990). All in-text citations were converted to numbered square brackets and the bibliography reformatted in ACS style, numbered by order of first citation.

Location of revision: Throughout the manuscript; References section (fully reformatted, in red).

7.

Research Methodology: Strengthen the justification for purposive sampling and briefly acknowledge possible selection bias and its implications.

Thank you for this important methodological comment. Section 3.3 now justifies purposive sampling explicitly: given the early diffusion stage of C3DP in Egypt, the population of professionals with meaningful exposure is small and cannot be enumerated, so probability sampling would have produced a predominantly uninformed sample. The revision also acknowledges the associated selection-bias risk (over-representation of technology-aware and contractor-affiliated professionals) and its implications for generalizability, cross-referenced to the limitations in Section 5.2.

Location of revision: Section 3.3, paragraph 1 (extended, in red); Section 5.2.

8.

Research Methodology: Strengthen the justification of sample adequacy for PLS-SEM by relying on statistical power analysis rather than only rule-of-thumb thresholds.

Thank you for this constructive suggestion. The rule-of-thumb statement has been replaced with a formal justification based on two complementary procedures: (i) an a priori power analysis in G*Power 3.1 (linear multiple regression, seven predictors, f² = 0.15, α = 0.05, power = 0.80), yielding a minimum of 103 respondents; and (ii) the inverse square root method of Kock and Hadaya (2018) applied to the smallest expected path coefficient (β = 0.213), yielding approximately 137 respondents. The obtained sample (n = 157) exceeds both requirements. Supporting citations (Cohen, 1992; Faul et al., 2009; Kock & Hadaya, 2018; Hair et al., 2019) were added.

Location of revision: Section 3.3, paragraph 4 (in red); echoed in the Abstract.

9.

Research Methodology: Clarify how the 35 indicators were developed, refined, and validated from prior studies.

Thank you for this helpful comment. A new paragraph in Section 3.3 now describes the three-stage development of the measurement indicators: (i) deductive generation from prior validated CSF and 3DP-adoption studies mapped to the constructs in Table 5; (ii) screening for redundancy and contextual relevance, with a content-validity review by a panel of academics and senior practitioners; and (iii) pilot testing with construction professionals before final refinement. In preparing this clarification we also corrected an inconsistency: the final instrument comprises 39 reflective indicators (31 CSF indicators plus 8 indicators of the 3DPA construct), consistent with Table 7; the questionnaire description was updated accordingly.

Location of revision: Section 3.3, new paragraph after the questionnaire description (in red).

10.

Results and discussion: Strengthen the theoretical contribution by clearly showing how the seven CSFs extend the classical TOE framework.

Thank you for this valuable comment. Section 5.1 has been rewritten to articulate three specific extensions of the classical TOE framework: (i) decomposition of the three generic contexts into seven measurable, construction-specific CSF constructs, converting an explanatory taxonomy into a testable structural model; (ii) empirical quantification of the relative weight of each context, revealing the dominance of organizational and technology-resource factors in a developing market—an ordering classical TOE does not predict a priori; and (iii) positioning of sustainability orientation (SEI) as an explicit, empirically distinct environmental sub-construct. A parallel statement was added to Section 2.5.

Location of revision: Section 5.1, paragraph 3 (rewritten, in red); Section 2.5.

11.

Results and discussion: Improve consistency by aligning the limitations with earlier methodological claims, particularly regarding sample composition, respondents’ familiarity level, and generalizability.

Thank you for this careful observation. Section 5.2 has been rewritten so that each limitation now corresponds explicitly to the methodological choices reported in Section 3: the purposive sampling strategy and its selection bias; the respondent profile (62.4% early-career, 51.6% unfamiliar with 3DP) and the resulting “adoption readiness” interpretation; the distinction between statistical power adequacy and population generalizability; and the reliance of the new case-study benchmarking on secondary sources.

Location of revision: Section 5.2 (rewritten, in red).

12.

Conclusion: Strengthen the conclusion by clearly highlighting the study’s theoretical contribution to the TOE framework beyond mere empirical validation.

Thank you for this constructive comment. The Conclusions now state the theoretical contribution explicitly: by disaggregating the TOE contexts into seven measurable CSF constructs, quantifying their relative influence, and embedding sustainability as an explicit environmental sub-dimension, the study transforms TOE into an operational, weight-ranked adoption model for construction 3DP in developing economies. An editorial leftover sentence (“Contrary to the wording used in the earlier draft…”) was also removed.

Location of revision: Section 6, paragraph 1 (in red).

13.

Conclusion: Better emphasize the scalability and practical implementation pathway of 3DP adoption in developing countries.

Thank you for this helpful suggestion. The Conclusions now present an explicit, scalable three-stage implementation pathway—(i) awareness, training, and government-sponsored pilots; (ii) local material supply chains, BIM-to-print workflows, and cost/schedule benchmarks; (iii) regulatory codification, certification, and liability frameworks—and note that the framework constructs are not country-specific and can be recalibrated in other developing markets.

Location of revision: Section 6, paragraph 2 (in red).

14.

Quality of English: Ensure consistent tense usage by standardizing the description of methodology and results, avoiding unnecessary shifts between past and present tense.

Thank you for this comment. The manuscript was proofread for tense consistency: procedures and findings are reported in the past tense (e.g., “the study interpreted…” in Section 4.2), while the present tense is reserved for interpretations and references to tables and figures. A redundant present-tense paragraph duplicating the model-quality results in Section 4.6 was deleted and the remaining paragraph consolidated.

Location of revision: Sections 3 and 4 throughout; Section 4.6 (deleted duplicate paragraph, struck through in red).

15.

Quality of English: Ensure consistent terminology and capitalization by standardizing the definition and usage of “Construction 3D Printing (C3DP)” throughout the manuscript.

Thank you for this observation. Terminology has been standardized: “Construction 3D Printing (C3DP)” is defined once, at first mention in the Introduction; the duplicate definition in Section 2.1 was replaced with the abbreviation; C3DP is used when referring specifically to the construction application and 3DP when referring to the technology generally; and construct acronyms (e.g., 3DPA) were left unchanged for consistency with the model. Capitalization was unified accordingly.

Location of revision: Section 1, paragraph 2; Section 2.1 (in red); checked throughout.

16.

Quality of English: Address minor grammatical issues, including incorrect or missing articles (the, a, an) and preposition errors in several sections.

Thank you for this careful reading. The manuscript was fully proofread. Corrections include, among others: “acceptance of the technology” (Section 5); removal of the erroneous word “stationary” (Section 4.3); unification of “labour” spelling; correction of caption errors (“Table 2. D Printing Significant Barriers” → “Significant barriers to construction 3D printing adoption”; “Discriminate validity” → “Discriminant validity”); “ISO/ASTM 52939:2023” notation; “Note:” formatting; and renumbering of the Recommendations list (1–5).

Location of revision: Throughout the manuscript (all marked in red).

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Reviewer 2 Comment

Response

1.

The supporting evidence for the conclusions is weak. The assertion that technological readiness is insufficient to integrate these changes into construction is relevant, but relying on a narrow survey casts doubt on its reliability and dilutes its originality, as it is similar to other technological shifts.

Thank you for this candid and constructive assessment. We have strengthened the evidential basis of the conclusions in four ways. First, the survey evidence is now explicitly triangulated: the RII barrier ranking and the PLS-SEM structural estimates are complemented by a new cross-country benchmarking of documented C3DP implementations (Section 2.3), which independently reproduces the barrier pattern found in our data. Second, sample adequacy is now formally demonstrated through statistical power analysis (Section 3.3). Third, the claims in the Conclusions were tempered and reframed as evidence of current adoption readiness rather than definitive expert consensus, with the limitations aligned accordingly (Section 5.2). Fourth, the originality of the study is now articulated through its specific theoretical extension of the TOE framework (Sections 2.5 and 5.1) rather than through the survey alone.

Location of revision: Sections 2.3, 3.3, 5.1, 5.2, and 6 (all revisions in red).

2.

The argument could be strengthened by presenting some details about the construction industry in Egypt and its regional variations.

Thank you for this helpful suggestion. The Introduction now characterizes the Egyptian construction industry—one of the largest and most labour-intensive markets in Africa, dominated by national housing and infrastructure programmes and conventional cast-in-place methods with substantial waste generation—and describes its regional differentiation: large urban programmes concentrated in Greater Cairo and the Nile Delta versus considerable housing demand in remote desert and Upper Egypt regions, where high transport and labour-mobilization costs make on-site automated fabrication particularly attractive.

Location of revision: Section 1, paragraph 3 (in red), supported by [5,6].

3.

This study also can document experimental cases of 3D-printed construction adoption in similar countries, analyzing their progress and weaknesses to compare them with surveys.

Thank you for this excellent suggestion. Two new paragraphs were added to Section 2.3 documenting implementation experiences in comparable markets: the UAE (regulatory institutionalization and government-backed pilots), Saudi Arabia (large-scale gantry printing exposing import and expertise dependence), India (academia–industry pilot houses facing certification, financing, and workforce constraints), and Nigeria and Sri Lanka (early-stage awareness and cost barriers), together with remote-area housing applications. The analysis then compares these experiences with our survey results, showing that the documented pattern—success under governmental sponsorship, local material development, and structured training; stagnation without regulatory pathways and skilled operators—mirrors the barrier structure identified empirically in Section 4.3.

Location of revision: Section 2.3, two new paragraphs after Table 4 (in red).

4.

The presentation of results, which are mostly presented in numerical tables, can be complemented with colors or graphs to facilitate understanding and correlation.

Thank you for this valuable suggestion. Three enhancements were made: (i) a new Figure 6 was added presenting the path coefficients (β) and effect sizes (f²) of all seven constructs as a colour-coded bar chart, allowing direct visual comparison of the structural results in Table 9; (ii) the importance bands in Table 6 are now colour-coded (green for High, amber for High–Medium); and (iii) explicit callouts to Figures 5 and 6 were added in the text to connect the tables with their graphical counterparts.

Location of revision: Section 4.6, new Figure 6; Section 4.3, Table 6 (colour-coded) and revised paragraph above it.

5.

This includes exploring the originality and review of specific characteristics that hinder or enhance 3D-printed construction, particularly the assessment of the speed and versatility of this technology, the complexities of investment in equipment and human training, and the restructuring of management.

Thank you for this insightful comment. A new paragraph was added to the Discussion analysing exactly these characteristics: the conditional nature of speed and versatility advantages (greatest for customized, geometrically complex elements and diminishing for simple repetitive components); the magnitude and partial irreversibility of investments in printers, printable materials, and digital infrastructure—particularly onerous under currency volatility and import dependence; the systematic retraining required for operators, designers, and project managers; and the necessary restructuring of management around digital workflows, quality control, procurement, and liability. The paragraph links these characteristics to the empirical dominance of SPM and RTO in the structural model.

Location of revision: Section 5, new paragraph after the PRC discussion (in red).

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Reviewer 3 Comment

Response

1.

Strengthen the sustainability contribution by linking the adoption framework to measurable sustainability outcomes, such as waste reduction, embodied carbon, material efficiency, energy use, safety, affordability, or life-cycle performance.

Thank you for this important comment, which goes to the heart of the journal’s scope. The sustainability contribution has been strengthened by explicitly linking the adoption framework to measurable sustainability outcomes. A new passage in Section 5.1 now connects the framework to quantifiable indicators: formwork elimination and near-net-shape deposition and their reported construction-waste reductions of roughly 30–60% [3,4,24]; topology-optimized and hollow-core printed sections and the associated reduction in material consumption per structural element [23,24]; automation-related removal of workers from hazardous manual tasks and the corresponding safety gains [24,30]; affordability gains illustrated by the documented cost comparison for a standard wall element (Table 4); and life-cycle performance, including the LCA evidence that the net embodied-carbon and energy balance depends critically on binder content and mix design, so that cement-rich printable mixes can offset the geometric material savings [2,21,32]. The passage concludes by recommending that future applications of the framework pair each TOE context with quantified key performance indicators—waste intensity (kg/m²), embodied carbon (kgCO₂e/m²), material-use efficiency, energy consumption, recordable safety incidents, affordability, and life-cycle cost—so that adoption readiness can be evaluated against verified sustainability outcomes rather than perceptions alone. The Introduction was reinforced with the same linkage.

Location of revision: Section 5.1 (extended sustainability paragraph, in red); Section 1, paragraph 5.

2.

Clarify that the study assesses perceptions of adoption readiness, not actual implementation or verified performance of construction 3DP.

Thank you for this comment. This concern overlaps with issues raised in the first review round (Reviewer 1, Comment 11, and Reviewer 2, Comment 1), where the “adoption readiness” interpretation was first introduced. Our response to Reviewer 1, Comment 11, is reproduced verbatim below:

“Thank you for this careful observation. Section 5.2 has been rewritten so that each limitation now corresponds explicitly to the methodological choices reported in Section 3: the purposive sampling strategy and its selection bias; the respondent profile (62.4% early-career, 51.6% unfamiliar with 3DP) and the resulting “adoption readiness” interpretation; the distinction between statistical power adequacy and population generalizability; and the reliance of the new case-study benchmarking on secondary sources.
Location of revision: Section 5.2 (rewritten, in red).”

In response to the present comment, this clarification has now been made fully explicit and systematic throughout the manuscript: (i) the Abstract now states that the survey captures professionals’ perceptions of adoption readiness rather than verified implementation performance; (ii) Section 3.1 now contains an explicit scope statement to the same effect, covering all constructs including the dependent construct (3DPA); (iii) Sections 4.2 and 5 now interpret the respondent profile and the estimates accordingly; and (iv) claims of “validation” have been moderated throughout the manuscript (see also our response to Comment 9 below).

Location of revision: Abstract; Section 3.1; Sections 4.2 and 5; Sections 5.2 and 6 (all in red).

3.

Improve the questionnaire methodology by including item sources, construct definitions, pilot testing, respondent recruitment process, and inclusion/exclusion criteria.

Thank you for this constructive comment. Part of this concern (item sources, construct mapping, content validity, and pilot testing) was addressed in the first round in response to Reviewer 1, Comment 9, which is reproduced verbatim below:

“Thank you for this helpful comment. A new paragraph in Section 3.3 now describes the three-stage development of the measurement indicators: (i) deductive generation from prior validated CSF and 3DP-adoption studies mapped to the constructs in Table 5; (ii) screening for redundancy and contextual relevance, with a content-validity review by a panel of academics and senior practitioners; and (iii) pilot testing with construction professionals before final refinement. In preparing this clarification we also corrected an inconsistency: the final instrument comprises 39 reflective indicators (31 CSF indicators plus 8 indicators of the 3DPA construct), consistent with Table 7; the questionnaire description was updated accordingly.
Location of revision: Section 3.3, new paragraph after the questionnaire description (in red).”

In response to the present comment, Section 3.3 has been further extended to report: (i) the respondent recruitment process—invitations were distributed electronically through professional and institutional networks and construction organizations in Egypt; (ii) explicit inclusion criteria (professionals currently active in the Egyptian construction sector: engineers, architects, project managers, contractors, consultants, or academics engaged with the industry); (iii) explicit exclusion criteria (incomplete questionnaires, respondents outside the construction sector, and invariant response patterns, screened as reported in Section 4.1); and (iv) construct definitions—a brief definition of C3DP and of each construct was provided at the beginning of the corresponding questionnaire section to establish a common understanding among respondents, including those with limited prior exposure. Item sources remain traceable through the references mapped to each construct in Table 5.

Location of revision: Section 3.3 (extended, in red); Section 4.1.

4.

Address common method bias statistically, not only through procedural measures.

Thank you for this important methodological comment. Section 4.5 has been rewritten so that common method bias (CMB) is now addressed statistically in addition to the procedural safeguards. Statistically, we applied the full-collinearity variance inflation factor (VIF) assessment of Kock (2015) [49], which is recognized as more sensitive than Harman’s single-factor test, whose weaknesses are well documented [48]. The full-collinearity VIFs of the seven exogenous constructs range from 1.320 to 2.290, all well below the conservative 3.3 threshold, indicating that no pathological common variance contaminates the predictors. (For the endogenous construct, the full-collinearity VIF equals 1/(1 − R²) by definition and therefore restates the model’s explanatory power rather than providing an independent bias diagnostic.) Two further pieces of statistical evidence are now reported: first, the latent correlations among the seven CSF constructs are near zero (|r| = 0.001–0.194; Table 8), a pattern fundamentally inconsistent with a pervasive method factor, which would systematically inflate the correlations among all same-method constructs [48]; second, the high R² of the structural model arises from the additive accumulation of seven quasi-orthogonal moderate effects rather than from a single inflated common dimension. Procedurally, Section 4.5 now explicitly reports the anonymity of responses, the psychological separation of predictor and outcome items into distinct questionnaire sections, the provision of construct definitions, and neutral item wording. Finally, the residual limitation of single-source, cross-sectional perception data is acknowledged in Section 5.2, together with a recommendation to use marker variables, multi-wave measurement, or multi-informant designs in future research.

Location of revision: Section 4.5 (rewritten, in red); Sections 3.4 and 5.2; new references [48,49].

5.

Add HTMT ratios and, preferably, confidence intervals for the path coefficients to strengthen SEM reporting.

Thank you for this valuable suggestion; both additions have been made. First, discriminant validity is now additionally assessed using the heterotrait–monotrait ratio of correlations (HTMT) [47], reported in the new Table 9. All HTMT values are below the conservative 0.85 threshold: the largest value is 0.600 (SPM–3DPA), and all values among the seven exogenous CSF constructs are below 0.23, confirming the distinctiveness of the constructs. Second, 95% confidence intervals for all standardized path coefficients, computed from the bootstrap standard errors (10,000 resamples), have been added to the path-analysis table (now Table 10). None of the intervals includes zero (e.g., SPM [0.403, 0.567]; RTO [0.348, 0.491]; PRC [0.094, 0.331]), corroborating the significance of all seven hypothesized relationships. Sections 3.4, 3.5, 4.4, and 4.6 and the Abstract were updated accordingly, and the subsequent tables were renumbered (Tables 10 and 11).

Location of revision: Section 4.4, new Table 9 (HTMT); Section 4.6, Table 10 (new 95% CI column and revised Note); Sections 3.4 and 3.5; Abstract.

6.

Explain how the 32 literature-based barriers were reduced to the 17 survey-relevant barriers used in the analysis.

Thank you for identifying this gap in the methodological description. Section 4.3 has been rewritten to explain the reduction transparently. The literature synthesis identified 32 potential barriers, classified into six categories (Table 2). During the instrument-development procedure described in Section 3.3, these 32 barriers were screened by the content-validity panel and in the pilot test against three criteria: (i) contextual relevance to current Egyptian construction practice; (ii) non-redundancy, whereby closely overlapping literature items were merged into single survey items; and (iii) questionnaire economy, to limit respondent fatigue given the 39 indicators already required for the measurement model. This screening yielded 17 survey items covering all six barrier categories (three items each for material and equipment issues, design and technical challenges, worksite and environmental risks, labour and management challenges, and regulatory and economic barriers, and two items for awareness and cultural barriers), coded by category (e.g., LMC1–LMC3) as reported in Table 6. The earlier wording, which could be read as implying that respondents themselves discarded 15 barriers after the survey, has been corrected.

Location of revision: Section 4.3, paragraph 2 (rewritten, in red); Section 3.3; new note below Table 6.

7.

Improve all figures and tables for readability. Replace unexplained codes in figures with meaningful labels or provide clear legends.

Thank you for this comment. A related presentation concern was raised in the first round (Reviewer 2, Comment 4), to which we responded as follows:

“Thank you for this valuable suggestion. Three enhancements were made: (i) a new Figure 6 was added presenting the path coefficients (β) and effect sizes (f²) of all seven constructs as a colour-coded bar chart, allowing direct visual comparison of the structural results in Table 9; (ii) the importance bands in Table 6 are now colour-coded (green for High, amber for High–Medium); and (iii) explicit callouts to Figures 5 and 6 were added in the text to connect the tables with their graphical counterparts.
Location of revision: Section 4.6, new Figure 6; Section 4.3, Table 6 (colour-coded) and revised paragraph above it.”

In response to the present comment, all remaining unexplained codes are now defined where they appear: (i) the caption of Figure 4 now defines every construct abbreviation (SPM, RTO, SCE, ICD, SEI, PRC, OS, 3DPA); (ii) a note below Table 6 now defines the barrier category codes (DTC, LMC, AC, ME, RE, WER), explains the within-category numbering, cross-references the full barrier statements in Table 2, and defines the colour-coded importance bands; (iii) the caption of Figure 5 now spells out the five barrier codes it displays; and (iv) a note below Table 7 cross-references the construct abbreviations. Table numbering and figure callouts were rechecked throughout following the insertion of the new HTMT table.

Location of revision: Captions of Figures 4 and 5; notes below Tables 6 and 7 (all in red).

8.

Discuss the implications of the respondent profile more critically, especially the high proportion of early-career professionals and respondents unfamiliar with construction 3DP.

Thank you for this comment. This concern overlaps with Reviewer 1, Comment 11, addressed in the first round; that response is reproduced verbatim below:

“Thank you for this careful observation. Section 5.2 has been rewritten so that each limitation now corresponds explicitly to the methodological choices reported in Section 3: the purposive sampling strategy and its selection bias; the respondent profile (62.4% early-career, 51.6% unfamiliar with 3DP) and the resulting “adoption readiness” interpretation; the distinction between statistical power adequacy and population generalizability; and the reliance of the new case-study benchmarking on secondary sources.
Location of revision: Section 5.2 (rewritten, in red).”

In response to the present comment, the implications of the respondent profile are now discussed more critically in two places. Section 4.2 now makes explicit the mechanisms through which the profile could influence the results: respondents unfamiliar with C3DP necessarily evaluate expected rather than experienced enablers, which can introduce optimism bias and blur distinctions between adjacent constructs, while early-career respondents may over-weight training and digital-workflow considerations relative to the contractual, liability, and financing constraints that senior practitioners would emphasize. Section 5 now explains why the sample nevertheless remains informative for the study’s stated purpose—an adoption-readiness assessment in a market where C3DP diffusion is minimal and a large implementation-experienced expert population does not yet exist—while noting that 93% of respondents are industry practitioners. Both sections now explicitly call for follow-up studies using expert-only panels (senior contractors, project managers, technology suppliers, regulators, and clients with direct 3DP project experience) and stratified comparisons by familiarity, experience, and organization type.

Location of revision: Section 4.2 (extended, in red); Section 5 (extended sample-characteristics paragraph, in red); Section 5.2.

9.

Moderate claims of a “validated framework.” A more appropriate formulation would be “an empirically tested framework based on perception survey data.”

Thank you for this fair observation, which we accept. The manuscript no longer claims a “validated framework.” The Abstract, the third research objective (Section 1), and Sections 2.5, 2.6, 3.1, 3.2, 3.4, 4.6, 5.1, and 6 have been reworded to describe “an empirically tested framework based on perception survey data,” precisely as suggested, and cognate verbs (“validate”, “validation”) describing the study’s own contribution have been replaced by “empirically test”/“empirical testing” throughout. The terms “validity” and “validation” are retained only in their standard psychometric sense (content, convergent, and discriminant validity) and in the CRediT author-contribution taxonomy.

Location of revision: Abstract; Sections 1, 2, 3, 4.6, 5.1, and 6 (throughout, in red).

10.

Revise the English, formatting, captions, labels, table numbering, and figure references carefully, as several editorial and presentation issues remain.

Thank you for this comment. Editorial and language issues were addressed extensively in the first round (Reviewer 1, Comments 14–16); those responses are reproduced verbatim below:

“Response to Reviewer 1, Comment 14: Thank you for this comment. The manuscript was proofread for tense consistency: procedures and findings are reported in the past tense (e.g., “the study interpreted…” in Section 4.2), while the present tense is reserved for interpretations and references to tables and figures. A redundant present-tense paragraph duplicating the model-quality results in Section 4.6 was deleted and the remaining paragraph consolidated.
Location of revision: Sections 3 and 4 throughout; Section 4.6 (deleted duplicate paragraph, struck through in red).”

“Response to Reviewer 1, Comment 15: Thank you for this observation. Terminology has been standardized: “Construction 3D Printing (C3DP)” is defined once, at first mention in the Introduction; the duplicate definition in Section 2.1 was replaced with the abbreviation; C3DP is used when referring specifically to the construction application and 3DP when referring to the technology generally; and construct acronyms (e.g., 3DPA) were left unchanged for consistency with the model. Capitalization was unified accordingly.
Location of revision: Section 1, paragraph 2; Section 2.1 (in red); checked throughout.”

“Response to Reviewer 1, Comment 16: Thank you for this careful reading. The manuscript was fully proofread. Corrections include, among others: “acceptance of the technology” (Section 5); removal of the erroneous word “stationary” (Section 4.3); unification of “labour” spelling; correction of caption errors (“Table 2. D Printing Significant Barriers” → “Significant barriers to construction 3D printing adoption”; “Discriminate validity” → “Discriminant validity”); “ISO/ASTM 52939:2023” notation; “Note:” formatting; and renumbering of the Recommendations list (1–5).
Location of revision: Throughout the manuscript (all marked in red).”

In response to the present comment, a further editorial pass was performed on the revised manuscript: captions and legends were expanded (see Comment 7), tables were renumbered consistently after the insertion of the new HTMT table (Tables 9–11), figure callouts were rechecked against the figures, long multi-clause sentences were split, and redundant wording was removed to improve readability and conciseness.

Location of revision: Throughout the manuscript.

11.

Comments on the Quality of English Language: Revise the English to be more readable and concise.

Thank you for this comment. Please see our response to Comment 10 above. A dedicated proofreading pass focused specifically on readability and conciseness: long sentences were split, nominalizations and redundant qualifiers were removed, and terminology was kept consistent (C3DP, 3DPA, and the construct names) throughout the manuscript.

Location of revision: Throughout the manuscript.

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Reviewer 4 Comment

Response

1.

The theoretical contribution is limited. The TOE framework and the seven proposed factors have already been widely discussed in technology adoption, construction management, and innovation diffusion studies. At present, the paper mainly applies existing factors to the Egyptian 3D printing context. The authors should make clearer what is new, why these seven factors are the most critical, and whether the TOE framework works differently in Egypt or other developing-country settings.

Thank you for this substantive comment. The core of this concern was raised in the first round (Reviewer 1, Comment 10), to which we responded verbatim as follows:

“Thank you for this valuable comment. Section 5.1 has been rewritten to articulate three specific extensions of the classical TOE framework: (i) decomposition of the three generic contexts into seven measurable, construction-specific CSF constructs, converting an explanatory taxonomy into a testable structural model; (ii) empirical quantification of the relative weight of each context, revealing the dominance of organizational and technology-resource factors in a developing market—an ordering classical TOE does not predict a priori; and (iii) positioning of sustainability orientation (SEI) as an explicit, empirically distinct environmental sub-construct. A parallel statement was added to Section 2.5.
Location of revision: Section 5.1, paragraph 3 (rewritten, in red); Section 2.5.”

In response to the present comment, Section 5.1 has been further extended to answer the three specific questions posed. What is new: the contribution is not the discovery of previously unknown factors but the disaggregation of the TOE contexts into seven measurable, construction-specific constructs and the quantification of their relative weights in a market for which no SEM-based C3DP evidence previously existed. Why these seven: the constructs emerged from the systematic synthesis in Section 2.4 (Table 5) as the enabler domains most frequently and consistently associated with C3DP implementation success, and they jointly operationalize all three TOE contexts without conceptual overlap, as confirmed empirically by the discriminant-validity results (Fornell–Larcker, cross-loadings, and the new HTMT analysis in Table 9). Whether TOE works differently in Egypt: the evidence indicates that it does—whereas studies in advanced economies typically identify regulatory frameworks and technological maturity as the proximate enablers of digital-construction adoption, in Egypt policy and regulation exhibited the weakest effect (β = 0.213) and managerial capability the strongest (β = 0.485), implying that in early-diffusion, resource-constrained settings the binding constraints are internal capabilities rather than external institutions. This ordering is now articulated as a context-specific boundary condition for TOE-based adoption research in developing countries.

Location of revision: Section 5.1 (extended, in red); Sections 2.4 and 4.4.

2.

The sample raises concerns. Around 62.4% of respondents have only 0–5 years of experience, and 51.6% are not familiar with construction 3D printing. This may be acceptable if the study focuses on adoption readiness. However, if the goal is to identify success factors for actual implementation, the sample should include more experienced respondents, such as senior contractors, project managers, technology suppliers, regulators, clients, and experts with real 3D printing project experience.

Thank you for this comment. This concern was raised in the first round (Reviewer 1, Comments 7 and 11) and again by Reviewer 3 (Comments 2 and 8). Our first-round response to Reviewer 1, Comment 11, is reproduced verbatim below:

“Thank you for this careful observation. Section 5.2 has been rewritten so that each limitation now corresponds explicitly to the methodological choices reported in Section 3: the purposive sampling strategy and its selection bias; the respondent profile (62.4% early-career, 51.6% unfamiliar with 3DP) and the resulting “adoption readiness” interpretation; the distinction between statistical power adequacy and population generalizability; and the reliance of the new case-study benchmarking on secondary sources.
Location of revision: Section 5.2 (rewritten, in red).”

Consistent with the reviewer’s own observation, the study is now explicitly and consistently framed as an assessment of adoption readiness rather than of actual implementation: this framing now appears in the Abstract, Section 3.1, Section 4.2, Section 5, and the Conclusions, and the term “validated framework” has been replaced by “empirically tested framework based on perception survey data” throughout (see Reviewer 3, Comment 9). We would add that, because C3DP diffusion in Egypt is minimal, a population of professionals with real 3DP project experience large enough for SEM estimation does not yet exist in the country; purposive sampling targeted the accessible informed population, and 93% of respondents are industry practitioners. An implementation-focused replication using expert-only samples—senior contractors, project managers, technology suppliers, regulators, and clients with direct 3DP project experience—is now explicitly identified as the priority for future research.

Location of revision: Abstract; Sections 3.1, 4.2, 5, 5.2, and 6 (in red).

3.

Common method bias is not well addressed. All data come from the same questionnaire, at the same time, and from the same respondents. Both predictors and outcomes are perception-based. Since all seven paths are significant and the R² is very high, this issue should be taken seriously. The authors should report tests such as Harman’s single-factor test, full collinearity VIF, or a marker-variable test, and explain any procedural controls such as anonymity, item randomization, or psychological separation.

Thank you for this important comment. The same issue was raised by Reviewer 3 (Comment 4) and has been addressed in full as part of this revision. Our response is reproduced here:

Section 4.5 has been rewritten so that common method bias (CMB) is now addressed statistically in addition to the procedural safeguards. Statistically, we applied the full-collinearity variance inflation factor (VIF) assessment of Kock (2015) [49]—one of the tests explicitly suggested by the reviewer—which is recognized as more sensitive than Harman’s single-factor test, whose weaknesses are well documented [48]. The full-collinearity VIFs of the seven exogenous constructs range from 1.320 to 2.290, all well below the conservative 3.3 threshold, indicating that no pathological common variance contaminates the predictors. (For the endogenous construct, the full-collinearity VIF equals 1/(1 − R²) by definition and therefore restates the model’s explanatory power rather than providing an independent bias diagnostic.) Regarding the concern that all seven paths are significant and R² is very high: two features of the results argue directly against a CMB explanation. First, the latent correlations among the seven CSF constructs are near zero (|r| = 0.001–0.194; Table 8)—if a common method factor drove the responses, all same-method constructs would correlate substantially and positively [48], which is not observed. Second, the high R² arises from the additive accumulation of seven quasi-orthogonal moderate effects, not from a single inflated common dimension. Procedurally, Section 4.5 now explicitly reports anonymity of responses, psychological separation of predictor and outcome items into distinct questionnaire sections, provision of construct definitions, and neutral item wording (item randomization was not employed and is therefore not claimed). The residual limitation of single-source, cross-sectional perception data is acknowledged in Section 5.2, with marker-variable, multi-wave, and multi-informant designs recommended for future research.

Location of revision: Section 4.5 (rewritten, in red); Sections 3.4 and 5.2; new references [48,49].

4.

Discriminant validity needs stronger evidence. The paper reports Fornell–Larcker and cross-loadings, but HTMT is now commonly expected in PLS-SEM studies. HTMT should be added in the current paper, especially because some constructs may overlap conceptually, such as organizational support and strategic project management.

Thank you for this suggestion. The same issue was raised by Reviewer 3 (Comment 5), in response to which the HTMT analysis has been added: discriminant validity is now additionally assessed using the heterotrait–monotrait ratio of correlations (HTMT) [47], reported in the new Table 9, and Sections 3.4, 3.5, and 4.4 were updated accordingly. All HTMT values are below the conservative 0.85 threshold: the largest value is 0.600 (SPM–3DPA), and all values among the seven exogenous CSF constructs are below 0.23. Regarding the specific concern about conceptual overlap between Organizational Support (OS) and Strategic Project Management (SPM): the empirical evidence indicates that the two constructs are clearly distinct—their latent correlation is 0.027 and their HTMT value is 0.034, far below any threshold of concern. This distinctness is consistent with the construct definitions, which are now reiterated in Section 4.4: OS captures top-management commitment and the availability of organizational resources, whereas SPM captures the planning, scheduling, and leadership practices through which projects are executed.

Location of revision: Section 4.4 (extended, in red), new Table 9 (HTMT); Sections 3.4 and 3.5; new reference [47].

5.

The model is too simple. All seven factors are modeled as direct predictors of 3D printing adoption, which makes the framework look more like a multiple-predictor model than a theory-driven mechanism. In reality, these factors may interact. For example, organizational support may affect strategic project management, policy support may affect resource and technology optimization, and resource optimization may mediate the link between policy support and adoption. The authors should either test such mechanisms or better justify the direct-effect-only model.

Thank you for this thoughtful comment. We agree that richer mechanisms are conceptually plausible, and, following the second option offered by the reviewer, the revised manuscript now justifies the direct-effects specification explicitly in a new paragraph in Section 3.6, on four grounds. First, theoretically, the TOE framework conceptualizes the technological, organizational, and environmental contexts as parallel antecedent conditions of adoption rather than as a causal chain [14]; a direct-effects specification is therefore the model most faithful to the framework under examination. Second, as the first SEM-based examination of C3DP adoption in Egypt, the study aims to establish baseline estimates of each factor’s direct influence before more elaborate mechanisms are imposed on the data. Third, with n = 157, the seven-predictor direct model preserves the statistical power established a priori in Section 3.3, whereas additional mediating chains would multiply the number of structural parameters and reduce the precision of every estimate. Fourth—and decisively—the data themselves provide no empirical support for the specific inter-factor mechanisms suggested: the latent correlations among the seven CSFs are near zero (Table 8), including precisely the pairs the reviewer proposes (OS–SPM: r = 0.027; PRC–RTO: r = −0.194, i.e., slightly negative). A mediation structure such as PRC → RTO → 3DPA or OS → SPM → 3DPA cannot be sustained by these data, as the bivariate foundations of the intermediate paths are absent. We have therefore retained the direct-effects model while adding the conceptually plausible mediation and interaction mechanisms as an explicit agenda for future longitudinal and multi-wave research in Section 5.2, where such designs could detect dynamic dependencies that a cross-sectional survey cannot.

Location of revision: Section 3.6, new final paragraph (in red); Section 5.2.

6.

The term “mixed-method approach” is misleading. The study mainly uses literature review, survey data, RII, and PLS-SEM, but does not include clear qualitative data collection or analysis, such as interviews, case studies, or coding. Unless a real qualitative component is added, the authors should rename the design as a “literature-informed quantitative survey design” or a “sequential exploratory-confirmatory quantitative design.”

Thank you for this fair observation, which we accept. The design has been renamed exactly as suggested: the manuscript now describes a “literature-informed, sequential exploratory–confirmatory quantitative survey design.” The term “mixed-method” has been removed from Section 1 and Section 3.1, and Section 3.1 now states explicitly that the design contains no qualitative strand of data collection or analysis: the exploratory component is literature-based, and all primary data are quantitative.

Location of revision: Section 1 (objectives paragraph); Section 3.1 (in red).

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Reviewer 1 Comment (Round 2)

Response

1.

I have reviewed the revised manuscript and noted the efforts made by the authors to address my comments and improve the quality of the manuscript. The revisions have adequately addressed my concerns. Therefore, I recommend accepting the revised manuscript for publication.

We sincerely thank the reviewer for the careful evaluation of our revisions across both rounds and for recommending the manuscript for publication. No further changes were requested; the reviewer’s earlier comments have shaped the manuscript substantially, and we are grateful for them.

Location of revision: No further revision required.

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Reviewer 2 Comment (Round 2)

Response

1.

First, it acknowledges the interviewees’ lack of knowledge and experience in the sector, which is why the title should be renamed as an evaluation of prior perceptions rather than success factors, emphasizing from the outset its methodological contribution in the initial assessment rather than in implementation.

Thank you for this constructive suggestion, which we accept. The title has been revised to foreground, from the outset, the perception-based and readiness-oriented (pre-implementation) scope of the study; it now reads: “Assessing Perceived Critical Success Factors for Construction 3D Printing Adoption Readiness in Egypt Through Structural Equation Modelling.” We respectfully retained the established term “critical success factors” because it denotes the constructs examined and preserves continuity with the CSF literature from which the measurement model was built; the added qualifiers “perceived” and “adoption readiness” make explicit that what is evaluated is professionals’ prior perceptions in an initial, pre-implementation assessment rather than verified implementation success. Consistent adjustments were made at the points a reader encounters first: the Abstract now states that the framework evaluates the perceived CSFs shaping readiness for 3DP adoption; the first research objective specifies that factors are identified and prioritized “as perceived by industry professionals”; and “adoption readiness” and “perception survey” were added to the keywords. These changes complement the framing already embedded throughout the manuscript in the previous round (Abstract; Sections 3.1, 4.2, 5, and 6), in which the study is explicitly presented as a perception-based adoption-readiness assessment and every claim of a “validated framework” was replaced by “empirically tested framework based on perception survey data.”

Location of revision: Title; Abstract (sentences 2 and 5); Section 1, first research objective; Keywords.

2.

Second, it needs to provide greater clarity regarding the characteristics of Egyptian construction in relation to 3DCP, for example, thermal and structural requirements for double-walled or reinforced constructions, regular use of solid systems, and typologies of single or multiple stories, lateral clearance area, provision of cementitious mixtures, etc. These are critical factors for the application of this technology and may differentiate Egypt from other developing countries. The document also needs to address the collaboration of companies in technological development and government support. Because aspects conducive to technology are visible, such as climate, morphology, or social or professional networks that support it.

Thank you for this insightful comment. A new paragraph has been added to the Introduction characterizing precisely these features of the Egyptian context and their implications for C3DP deployment: (i) structural systems and typologies—the dominance of reinforced-concrete skeleton systems with solid masonry infill walls, and the range from single-storey rural dwellings to the repetitive multi-storey blocks of the national housing programmes; (ii) thermal and structural requirements—the hot, arid climate’s demand for thermal mass, increased wall thickness, or cavity (double-wall) envelope configurations, which printed walls would need to reproduce (e.g., hollow-core or double-skin printed sections) while accommodating the reinforcement detailing required by national concrete and seismic design codes; (iii) site conditions and lateral clearance—dense urban infill plots in Greater Cairo with limited clearance for gantry printers versus open, repetitive desert-city and remote-settlement layouts well suited to large-format gantry and crane systems, with the predominantly dry climate favouring continuous on-site printing; (iv) provision of cementitious mixtures—Egypt’s large domestic cement industry supplies the cementitious base locally, while specialized admixtures and printing systems remain import-dependent; and (v) the institutional environment—visible enablers (state-led housing and infrastructure programmes, an established professional-engineering community, and emerging university–industry collaboration) alongside the absence of dedicated regulatory pathways, making government support and inter-firm collaboration in technological development decisive conditions, captured in the model through the PRC and OS constructs. The paragraph is grounded in the sources already cited for the Egyptian and regional context [5–7,24]. In addition, a linked sentence in the Discussion’s implementation-pathway paragraph now connects these conditions to the three-stage adoption roadmap (domestic cementitious supply, repetitive state-housing typologies, desert sites suited to gantry systems, and printable-mixture certification with code-consistent reinforcement detailing).

Location of revision: Section 1, new paragraph 4 (after the Egyptian market paragraph); Section 5, implementation-pathway paragraph (final sentence).

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Reviewer 3 Comment (Round 2)

Response

1.

The sustainability contribution should remain carefully worded as prospective rather than empirically demonstrated.

Thank you for this important nuance, which we fully accept. The sustainability passages have been re-audited and reworded so that every benefit is stated as prospective: in Section 5.1, “translate into quantifiable reductions” now reads “can translate into quantifiable reductions,” “reduce material consumption” now reads “can reduce material consumption,” and “removes workers from hazardous manual tasks, improving measurable safety performance” now reads “can remove workers from hazardous manual tasks, with the potential to improve safety performance.” A new closing sentence makes the epistemic status explicit: “these sustainability benefits remain prospective for Egypt: they are reported in the international literature but have yet to be demonstrated empirically in Egyptian C3DP projects.” The final sentence of the Abstract was likewise softened to “can support the prospective implementation of sustainable construction technologies.” The existing KPI recommendation already frames verification as a future task, and the life-cycle trade-off caveat (binder content and mix design) is retained.

Location of revision: Section 5.1, sustainability paragraph (reworded, with new closing sentence); Abstract, final sentence.

2.

Figures 4 and 5 and Table 7 should be further improved for readability.

Thank you for this suggestion. Three changes were made. Figure 4 (the structural model with outer loadings) was enlarged from 14.6 cm to 17.5 cm in width (full text-column width), materially increasing the legibility of the loading values and construct labels; its caption retains the full legend of construct abbreviations. Figure 5 (top five barriers) was likewise enlarged to full text-column width, and its caption retains the spelled-out barrier codes. Table 7 was simplified by removing the duplicated interior header row that had been carried over from the original page layout; the table now has a single header, and—following the previous revision—each construct’s reliability statistics (α, ρa, ρc, AVE) are reported once per construct rather than repeated on every item row, with abbreviations defined in the table note.

Location of revision: Figure 4 and Figure 5 (resized); Table 7 (duplicated header row removed).

3.

The manuscript would also benefit from final editorial condensation, as some newly added passages are somewhat over-explanatory.

Thank you for this fair observation. The passages added in the previous round were condensed while preserving all substantive content requested by the four reviewers: Section 3.1 (the design clarification was reduced to a single clause: “no qualitative strand of data collection or analysis is involved”); Section 3.6 (the four-reason justification of the direct-effects specification was consolidated into one three-part sentence, shortening the passage by roughly 40%); Section 4.2 (meta-language such as “are now made explicit” was removed and the two mechanisms merged into one sentence); Section 4.5 (the comparison with Harman’s single-factor test was reduced to “in preference to the less sensitive Harman’s single-factor test”); Section 5 (the sample-profile mechanisms duplicated from Section 4.2 were replaced with a cross-reference); and Section 5.1 (“Beyond these extensions, two further clarifications sharpen the theoretical contribution” was shortened to “Two further clarifications follow”). All statistics, justifications, and reviewer-requested content remain intact.

Location of revision: Sections 3.1, 3.6, 4.2, 4.5, 5, and 5.1 (condensed; see tracked-changes version).

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Reviewer 4 Comment (Round 2)

Response

1.

All suggestions are addressed.

We sincerely thank the reviewer for confirming that all suggestions have been addressed and for the constructive comments provided in the previous round, which materially strengthened the methodological reporting of the study. No further changes were requested.

Location of revision: No further revision required.