3.2. Hierarchy Design
We designed a three-level hierarchy for evaluating low-rise terraced housing development and purchase decisions:
Level 1 (Goal): Overall priority in terraced housing decisions.
Level 2 (Dimensions): Five key dimensions.
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A1. Location Selection: Site characteristics and accessibility.
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A2. Housing Price: Cost and value considerations.
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A3. Financing: Capital and loan capacity.
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A4. Construction Risk: Technical and regulatory challenges.
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A5. Building Planning: Design and layout attributes.
Level 3 (Factors): Fourteen specific factors.
A1. Location Selection (3 factors): - A11. Transportation Convenience: Accessibility by both road and public transport, encompassing proximity to major roads, highway interchanges, bus routes, and commuting time to key employment centers. In non-metropolitan contexts, road-based commuting dominates, but access to public transit remains relevant for younger and car-free households. - A12. Living Function: Proximity to schools, hospitals, shopping, and daily services. - A13. Environmental Quality: Air quality, noise levels, green space, and neighborhood character.
A2. Housing Price (3 factors): - A21. Future Appreciation Potential: Expected property value growth based on area development trends. - A22. Price Acceptability: Alignment between asking price and buyer willingness to pay. - A23. Developer Cost: Total development cost including land acquisition, construction, and financing.
A3. Financing (2 factors): - A31. Buyer Repayment Capacity: Buyer’s ability to afford down payment and monthly mortgage payments. - A32. Developer Financing Capacity: Developer’s access to equity and debt financing for project execution.
A4. Construction Risk (3 factors): - A41. Construction Difficulty: Site conditions, structural complexity, and technical challenges. - A42. Government Regulations: Zoning, building codes, seismic requirements, and permit processes. - A43. Neighboring Residents/Community Relations: This factor captures stakeholder concerns arising from the immediate residential neighborhood, but each group approaches it from a structurally distinct vantage point.
Developer interpretation (construction-phase risk): The primary concern is mitigating disputes and damage claims from adjacent property owners during the build—specifically, risks of excavation-induced settlement, noise and vibration complaints, boundary encroachment, and access obstruction. From a project-management perspective, unresolved neighbor conflicts can trigger work stoppages, litigation, and cost overruns.
Homebuyer interpretation (post-occupancy environment): The primary concern is the quality of the surrounding community after move-in—neighbor compatibility, social cohesion, noise management, and the overall living atmosphere. For owner-occupiers in low-rise terraced housing, where shared walls and close proximity are structural features, neighbor relations directly affect residential satisfaction [
38].
Both interpretations are legitimate and internally consistent within the AHP framework, which measures relative importance rather than requiring construct identity across groups. The factor label was intentionally kept broad to allow each respondent group to weight it according to the dimension most salient to their decision context. We acknowledge this as a construct-level limitation and recommend that future studies operationalize A43 as two separate factors—one for construction-phase neighbor risk and one for post-occupancy community quality—to enable cleaner cross-group comparison.
A5. Building Planning (3 factors): - A51. Space Efficiency: Ratio of usable area to gross floor area. - A52. Floor Plan Layout: Room configuration, circulation, and functional zoning. - A53. Appearance: Facade design, materials, and aesthetic appeal.
This hierarchy was developed through the literature review and consultation with three experienced construction managers and two real estate agents in Changhua County. All fourteen factors are directly evaluated through pairwise comparisons; no factors are estimated or derived.
Figure 1 illustrates the three-level AHP hierarchy adopted in this study, consisting of the overall goal, five evaluation dimensions, and fourteen evaluation factors.
3.3. Study Area and Data Collection
This study is designed as an exploratory case study of Changhua County rather than a statistically representative survey of all non-metropolitan Taiwan. The purpose is to identify and compare priority structures within a specific regional housing market.
3.3.1. Why Changhua County?
Changhua County was selected as the study area for several reasons that collectively support its representativeness of non-metropolitan Taiwan.
Demographic scale: With a registered population of approximately 1.27 million (2023), Changhua is the most populous non-metropolitan county in Taiwan, providing a sufficiently large market to support meaningful sample sizes for both developer and homebuyer groups.
Housing stock profile: Low-rise terraced housing accounts for most residential units in Changhua County, consistent with the broader non-metropolitan pattern across central and southern Taiwan. The county’s housing stock is dominated by owner-occupied, low-rise structures rather than the high-rise condominium towers characteristic of metropolitan Taipei or Taichung.
Construction industry structure: The Changhua construction industry is composed primarily of small-to-medium local developers—firms with annual revenue below TWD 300 million—rather than the large national developers that dominate metropolitan markets. This structure is typical of non-metropolitan counties in Taiwan, where project scale and financing capacity differ markedly from metropolitan norms.
Regulatory environment: Changhua County operates under the same national building codes, seismic regulations, and land-use planning framework as other non-metropolitan counties, ensuring that findings related to the Construction Risk dimension (A4) are transferable to comparable jurisdictions.
We acknowledge that Changhua County represents one specific non-metropolitan context, and that priority structures may vary in other non-metropolitan counties (e.g., Yunlin, Chiayi, and Pingtung) that differ in land supply, infrastructure quality, or demographic composition. Replication in additional counties is recommended before broad generalizations are drawn.
3.3.2. Survey Administration
We conducted surveys in Changhua County, Taiwan, between March and May 2024. Two respondent groups were recruited:
Developer group (n = 35): Construction managers, project managers, and senior engineers from local development firms. Inclusion criteria: (1) minimum three years of experience in residential development, (2) direct involvement in at least two terraced housing projects in Changhua County, (3) participation in project planning or site selection decisions. Respondents were recruited through the Changhua County Construction and Development Industry Association. Mean experience: 8.2 years (range: 3–18 years). Firm size: 12 respondents from firms with annual revenue under TWD 100 million, 15 from firms with revenue of TWD 100–300 million, 8 from firms with revenue over TWD 300 million.
Homebuyer group (n = 58): Individuals who purchased terraced housing units in Changhua County between January 2022 and March 2024. Inclusion criteria: (1) primary residence purchase (not investment), (2) purchase decision made within the past two years, (3) willingness to complete a 30 min questionnaire. Respondents were recruited through real estate agencies, homeowner associations, and snowball sampling. Age distribution: 12 respondents aged 25–34, 23 aged 35–44, 16 aged 45–54, 7 aged 55–64. Household income: 18 respondents with annual income under TWD 1 million, 26 with income of TWD 1–1.5 million, 14 with income over TWD 1.5 million.
Each respondent completed a structured AHP questionnaire consisting of pairwise comparison matrices. The questionnaire included the following:
1 matrix comparing the 5 dimensions (10 pairwise comparisons).
1 matrix for A1 factors (3 comparisons).
1 matrix for A2 factors (3 comparisons).
1 matrix for A3 factors (1 comparison).
1 matrix for A4 factors (3 comparisons).
1 matrix for A5 factors (3 comparisons).
Total: 23 pairwise comparisons per respondent. Questionnaires were administered in person or via video call. Each comparison was explained verbally, and respondents were asked to indicate their preference using Saaty’s 1–9 scale. Questionnaires with CR > 0.10 at any level were flagged, and respondents were asked to review and revise inconsistent comparisons. A total of 11 questionnaires (8 from developers and 3 from homebuyers) required one round of revision; no questionnaire required more than one revision cycle. After revision, all questionnaires achieved CR ≤ 0.10.
Individual responses were aggregated using the geometric mean method, which preserves the reciprocal property of pairwise comparison matrices [
12]. For each pairwise comparison, the geometric mean of all respondents’ judgments was calculated and used to construct group-level comparison matrices for developers and homebuyers.
Because recruitment was conducted through professional associations, real estate agencies, homeowner associations, and snowball sampling, the exact number of individuals approached, the response rate, and the number of individuals declining participation were not systematically recorded. This limitation is acknowledged in
Section 5.4.
3.4. Consistency Check
The present study is intended as an exploratory comparison of aggregated AHP priorities rather than inferential statistical testing. Accordingly, the findings of this study should be interpreted as exploratory comparisons of stakeholder priorities rather than formal statistical inference.
All AHP calculations were performed using Microsoft Excel. Pairwise comparison matrices were constructed for each respondent, and priority vectors were derived using the principal eigenvector method. Consistency indices and consistency ratios were calculated following Saaty’s procedure. The Spearman rank correlation reported in
Appendix A was computed using Python 3.11 and SciPy (scipy.stats.spearmanr).
Consistency ratios (CRs) were calculated at each level of the hierarchy for both groups.
Table 1 reports CR values for all comparison matrices.
All consistency ratios are well below Saaty’s 0.10 threshold, indicating that both groups provided internally consistent judgments. The A3 dimension has only two factors, requiring only one pairwise comparison, which by definition is perfectly consistent (CR = 0.000).
Because the objective of this study was an exploratory comparison of aggregated stakeholder priorities, formal sensitivity analysis was not performed.