4.1. Empirical Clusters from K-Means
This section presents the results of a multi-level clustering analysis developed to classify countries according to a sequential layering of structural indicators. These include GNI per capita, the share of manufacturing in total output, dependence on resource exports, total factor productivity (TFP), the proportion of mid- and high-technology exports, capital stock per worker, and average wages. The core objective of this hierarchical framework is to uncover latent structural and technological differences across economies that are not adequately captured by income-based classifications. By incrementally incorporating additional variables at each stage, the model enables a more granular differentiation of development patterns and economic structures.
The clustering procedure begins with GNI per capita as the base layer, serving as a proxy for a country’s overall economic development and income level. This initial segmentation divides countries into broad macroeconomic categories based on national income. Following the methodology specified in the earlier section, the model identifies three income clusters using threshold values of
$2178 and
$16,856. Accordingly, Cluster 1 includes low-income economies (GNI between
$103.2 and
$2178.2), Cluster 2 represents middle-income economies (
$2185.9 to
$16,856.7), and Cluster 3 corresponds to high-income countries (
$16,874.4 to
$128,981.1), as summarized in
Table 2.
The second layer introduces structural differentiation based on the manufacturing share in total production, selected as the next most explanatory variable using an R-squared ranking. Each of the three income groups from the first layer is further subdivided into three categories according to their level of industrialization, producing a total of nine clusters. Specifically, countries are categorized as non-industrial, industrialized, or highly industrialized within their respective income tiers. For low-income countries, a manufacturing share below 12% defines non-industrial economies, between 12% and 20.3% defines industrialized economies, and above 20.3% corresponds to highly industrialized economies. In the middle-income group, the respective thresholds are 0.9–13.2% (non-industrial), 13.2–21.7% (industrialized), and 21.7–39.1% (highly industrialized). High-income economies are divided using the thresholds of 0–14.7%, 14.7–23.5%, and 23.6–37.3%. These divisions underscore the heterogeneity of production structures even among countries with comparable income levels. By the end of this layer, the classification expands to nine clusters reflecting joint income and industrialization characteristics (summarized in
Table 3).
The third layer incorporates resource export dependence as a differentiating variable, adding eight new splits and increasing the total number of clusters to seventeen. A threshold of approximately 60% has been established to differentiate between resource-dependent and diversified countries. For instance, within the low-income, non-industrial category, economies with resource exports ranging from 59.8% to 99.9% are classified as resource-dependent, whereas those with export shares between 11.5% and 59.5% are considered diversified. A similar cutoff (59.6%) applies to the middle-income, industrial group. In contrast, the high-income, highly industrialized group remains undivided due to a limited range of resource export levels (6.5% to 58.6%), indicating a greater degree of export diversification among the highly industrialized high-income countries. Ultimately, eight of the nine clusters from the preceding layer are divided based on this variable, with Group 9 remaining unchanged due to uniformly low levels of resource exports among its members (summarized in
Table 4).
In the following step, total factor productivity (TFP) was evaluated as a candidate for further subdivision. However, this variable did not yield any statistically meaningful splits within the existing clusters. The next layer introduces technological complexity, proxied by the share of mid- and high-technology exports in total exports. This indicator reflects both a country’s capacity for innovation and the sophistication of its production structure. Unlike previous variables that produced broader segmentation, technological complexity led to only two significant subdivisions. These emerged solely among middle-income, diversified, industrial economies—where the dispersion in technological export intensity was sufficiently pronounced to warrant further differentiation.
A clear pattern emerges: export complexity tends to increase with income level. The lower-income clusters could not be further subdivided based on this indicator due to their consistently low complexity values. Notably, the Highly Industrialized Diversified Low-income group boasts the highest export complexity at 36.7, significantly surpassing all other groups, with the next highest being the Industrialized Diversified group at 31.6 in terms of mid and high-tech goods export share of total exports. Certain middle- and high-income clusters, particularly those heavily reliant on resources, also displayed limited technological sophistication and remained undivided. In contrast, clusters exhibiting consistently high complexity showed no internal differentiation. Consequently, only two groups—Group 10 and Group 12—were differentiated based on share of mid and high-tech goods export in total exports.
Within the middle-income, industrial, diversified group, a threshold of 37.2% in mid- and high-tech exports delineated the cluster into two distinct subgroups: one characterized by low technological complexity (5.7–36.8%) and another exhibiting high complexity (37.2–76.9%). A comparable group division was observed in the middle-income, highly industrial, diversified cluster, where a 36.9% threshold separated countries with low export complexity (3.97–36.5%) from those with higher levels (36.9–79.3%). These refinements enhanced the granularity of the classification within this segment of the development spectrum. Other clusters, particularly within the low-income tier, were not further subdivided at this stage, as their members exhibited uniformly low levels of technological exports. Similarly, most high-income clusters already demonstrated consistently high export complexity, resulting in limited intra-group variation and precluding any meaningful additional stratification (summarized in
Table 5).
Capital stock per employee and average wage levels did not contribute to meaningful differentiation among the clusters at this stage.
In summary, the layered clustering procedure identified 19 distinct country groups, each defined by a unique combination of GNI per capita, the share of manufacturing in GDP, reliance on resource exports, and the proportion of mid- and high-technology exports. These clusters effectively capture the structural diversity of national economies across various dimensions, including income level, industrialization, resilience, specialization, and technological sophistication. Comprehensive empirical ranges and the harmonized labeling scheme—featuring operational definitions, cutoff values, and defining indicators—are detailed in
Appendix A (
Table A1 and
Table A2).
4.3. Structural Transition Pathways Before and After 1990
This section offers an overview of the transitions between cluster groups among countries, highlighting recurring development trajectories. Each transition is defined by its initial and final group, and the structural threshold specific to the transition crossed. For example, a move from Group 1 (Non-Industrial low-income) to Group 3 (Industrialized resource-dependent low-income) occurs when a country’s share in manufacturing surpasses the 12 percent threshold. In total, there were 198 between 1970 and 2019: 54 occurred before 1990, while 144 took place afterward. Among these transitions, 97 followed a manufacturing-led path, 26 were resource-led, and 75 indicated deindustrialization, with 66 of these occurring post-1990.
Figure 1,
Figure 2,
Figure 3 and
Figure 4 summarize the principal pathways analyzed in this paper;
Appendix C reports the full list of transitions, thresholds, and country cases.
Figure 1 shows the pre-1990 manufacturing-led path;
Figure 2 the post-1990 modified manufacturing path;
Figure 3 the East Asian manufacturing-concentration path; and
Figure 4 the resource-export path. In each figure, the vertical axis denotes manufacturing intensity, and the horizontal axis denotes income category. Solid lines indicate observed transitions; dashed lines indicate movements beyond the income–manufacturing plane. The right-hand panel lists group names and the thresholds used to define transitions.
The manufacturing-led path prior to 1990, illustrated in
Figure 2, outlines a typical sequence that captures 33 of the 54 economic transitions observed during this timeframe (
Appendix C,
Table A5). This trajectory follows an established developmental framework that begins with early industrialization, which is then followed by increases in income, diversification of exports, further industrialization, and growing complexity of exports, ultimately leading to the achievement of high-income status. Upon reaching high income, economies enter a post-industrial phase marked by deindustrialization.
Notably, the predominant early transition involved a shift from Group 1 (Non-industrial low-income) to Group 3 (Industrialized resource-dependent low-income), observed in six countries: Bolivia, Burundi, Cameroon, Malawi, Kenya, and Tunisia. However, it is significant to note that none of these nations achieved middle-income status during the interval from 1970 to 1990. Malaysia illustrates how an industrialized resource-dependent, low-income economy diversified into the middle-income range. In 1970, Malaysia was classified within Group 3, characterized by a gross national income (GNI) per capita of USD 1905, an overwhelming reliance on resource exports (approximately 92 percent), and a modest manufacturing sector contributing 13.7 percent to its GDP. Malaysia entered Group 9 (industrialized resource-dependent middle-income) once GNI per capita exceeded USD 2186. Notably, three countries accomplished this transition prior to 1990. By the mid-1980s, Malaysia had diversified sufficiently to progress to Group 10 (industrialized diversified middle-income), where manufacturing accounted for nearly 20.7 percent of GDP, resource exports made up 56 percent, and GNI reached approximately USD 4035. This transition was achieved by two countries in the pre-1990 period.
Singapore provides an illustrative example of the subsequent phases within the manufacturing-led economic pathway, advancing from Group 10 (Industrialized diversified middle income) to Group 19 (Highly industrialized complex high-income). By the 1970s, Singapore had already established itself as a diversified middle-income economy, with a GNI per capita of USD 7331. Through processes of industrial deepening, Singapore was elevated to Group 13 (Highly industrialized diversified middle income), a transition realized by other four economies before 1990. The rising complexity of its exports subsequently facilitated its advancement to Group 14 (highly industrialized complex middle income), a transition documented in five instances. By 1985, Singapore had surpassed the high-income threshold of USD 16,875, advancing to Group 19 (highly industrialized complex high-income). Manufacturing continued to rise, peaking at 27% of GDP in 2004. However, as the manufacturing share subsequently declined to below 23.6 percent, Singapore transitioned to Group 18 (Industrialized complex high-income) in 2008 despite maintaining its export sophistication. The proportion of medium- and high-technology goods was 58 percent upon entering Group 19 and increased slightly to 59 percent while in Group 18.
For context, among high-income economies, the transition from Group 19 to Group 18 during deindustrialization was a common trend. By 1970, some countries were already classified in Group 18, and between 1970 and 1990, seven additional nations—Hong Kong, Austria, Belgium, Denmark, Finland, France, and the Netherlands—shifted from Group 19 to Group 18 as their manufacturing shares fell below the 23.6% threshold, despite maintaining high export complexity. Group 18 encompasses manufacturing shares ranging from 23.6% to 14.7%; notably, in the pre-1990 sample, no high-income country recorded a manufacturing share below 14.7%.
Collectively, Malaysia and Singapore exemplify the comprehensive sequence of the pre-1990 manufacturing-led pathway, encompassing the early phases of industrialization and diversification in Malaysia, culminating in an increase in the complexity of exports and the attainment of high-income status, followed by subsequent deindustrialization in Singapore.
Figure 2 delineates the thresholds and indicator values that underlie these transitions.
Post-1990, the global landscape of economic development underwent a significant transformation due to widespread deindustrialization, altering the traditional manufacturing-led development path (See
Figure 3;
Appendix C,
Table A6). While some nations adhered to established developmental paradigms, deindustrialization emerged as a common phenomenon not only for high-income countries but also across middle and low-income economies, thereby disrupting the conventional sequence of structural advancements. Among the 144 documented transitions post-1990, nearly half (66 instances) represented deindustrialization events. Notably, 45 of these events occurred in low- and middle-income economies, in stark contrast to the single instance of deindustrialization in a low- or middle-income country prior to 1990, which was Colombia in 1987 (see
Appendix C,
Table A7).
At the high-income tier, the typical transition from Group 19 (highly industrialized complex high-income) to Group 18 (industrialized complex high-income) continued to be observed. Nine countries followed this pathway after 1990. However, since the 1990s, several advanced economies have experienced significant declines in manufacturing, reaching levels below 14.7%. This shift led to the appearance of Group 16 (deindustrialized complex high-income) in 1993, which includes economies characterized by sophisticated exports but minimal industrial capacity. An extreme example is Hong Kong, which transitioned to Group 16 through deindustrialization from Groups 19 and 18. Hong Kong achieved high-income status before 1990 with manufacturing contributing nearly 24% of its GDP. By 2019, manufacturing had dropped to about 1%, while export sophistication increased from 40% to 42% across its reclassifications from Group 19 to Group 18 and eventually to Group 16. In total, nine economies made the transition to Group 16 during the post-1990 period.
Within the middle-income category, a notable development was the dissolution of Group 13 (Highly industrialized diversified middle income). Before 1990, four economies, including Singapore, followed a deepening sequence in which manufacturing first rose above 21.7 percent of GDP to enter Group 13, and only then did export complexity increase sufficiently to reach Group 14 (Highly industrialized complex middle income). Post-1990, only two economies entered Group 13; both did so in 1991, and by 2007, Group 13 had effectively ceased to exist. Two forces explain the disappearance of Group 13 after 1990: first, four deindustrialization transitions led countries to regress from Group 13 to Group 10 (Industrialized diversified middle income); second, the trajectory of structural upgrades increasingly inclined toward a Group 11 (Industrialized complex middle income), which emerged post-1990 as a less industrialized counterpart to Group 14. Group 11 encompasses manufacturing shares ranging from 13.2 to 21.7 percent of GDP, coupled with export complexity indices above 37 percent. Seven transitions into Group 11 were recorded post-1990, all originating from Group 10. Advancement beyond Group 11 was infrequent, with only three economies progressing further—two into Group 16 and one into Group 18.
Shifting dynamics were also observed at the low-income level. Twelve economies regressed from Group 3 (Industrialized resource-dependent low-income) to Group 1 (Non-industrial low-income) as their manufacturing sectors fell below the 12 percent threshold. More significantly, a diversification-before-income growth pattern emerged, reversing the order of steps. Prior to 1990, countries in Group 3 typically transitioned to Group 9 (Industrialized resource-dependent middle-income) as their incomes increased, followed by diversification into Group 10. Post-1990, several economies adopted a diversification-first sequence, moving from Group 3 to Group 4 (Industrialized diversified low-income) even while remaining below the middle-income classification, before subsequently advancing to Group 10. In total, seven such transitions into Group 4 were noted, one instance with Tunisia occurring before 1990 and six thereafter, of which five later progressed from Group 4 to Group 10.
Tunisia serves as a representative case illustrating how these structural shifts altered the manufacturing-led pathway (
Figure 3). In 1970, Tunisia was classified in Group 1, with manufacturing contributing 9 percent to GDP, resource exports accounting for 81 percent, and a Gross National Income (GNI) per capita of USD 1149. As manufacturing surpassed the 12 percent threshold, Tunisia transitioned into Group 3. By 1986, as resource export dependence declined to below 59.6 percent, Tunisia shifted to Group 4 while remaining below the middle-income threshold. By 1994, GNI per capita exceeded USD 2186, enabling Tunisia to advance into Group 10. By 2010, export complexity reached 37 percent, although manufacturing experienced a slight decline from 16 percent to 15 percent, resulting in Tunisia’s classification in Group 11. As of 2019, GNI per capita had increased to USD 11,064, while manufacturing further declined to 14.3 percent. With the continued downward trend in manufacturing juxtaposed against stable export sophistication, Tunisia’s most plausible future trajectory suggests a shift towards Group 16 (this group encompasses a manufacturing share below 14.7%). Through this sequence, Tunisia illustrates how the post-1990 reordering operates in practice.
The second post-1990 route centered on unusually high manufacturing intensity, where economies’ manufacturing share in GDP exceeded the 20.3 percent threshold early in their development (see
Figure 4;
Appendix C,
Table A8). This path starts with an initial phase of industrialization, where countries advance from Group 1 to Group 3, followed by an increase in manufacturing intensity above 20.3 percent to reach Group 5. Before 1990, six countries entered Group 5 (Highly industrialized resource-dependent low-income). After 1990, only Myanmar joined Group 5, and it has remained in this category as of 2019. Subsequently, five East Asian economies: China, Vietnam, the Philippines, Indonesia, and Thailand subsequently reached Group 6 (Highly industrialized diversified low-income) by reducing their dependence on resource exports to below 59.6 percent, all while still being classified as low-income based on GNI thresholds. This transition mirrors the diversification shift from Group 3 to Group 4, where diversification precedes income growth. Conversely, countries outside East Asia that reached Group 5 failed to diversify, regressing instead back to Group 3 (Industrialized resource-dependent low-income).
Among the five East Asian nations, China, Vietnam, and Thailand successfully entered Group 14 (Highly industrialized complex middle-income) by combining high manufacturing intensity with increased export complexity and income. Following 1990, new entrants to Group 14 emerged solely through this pathway, moving from Group 5 to Group 6. The previously utilized deepening route that allowed transitions from Group 10 to Group 13 ceased to produce new entrants, with the exception of Malaysia. Malaysia’s ascent began earlier, reaching Group 13 in 1991 and subsequently increasing its complexity to move into Group 14 in 1998. By 2019, Group 14 consisted of four economies: Malaysia, China, Vietnam, and Thailand.
Not all five East Asian countries that transitioned to Group 6 converged with Group 14. The Philippines also reached Group 14 in 1993; however, it later faced deindustrialization, which led to its regression to Group 11 (Industrialized complex middle-income) by 2009. In contrast, Indonesia did not achieve Group 14. After moving from Group 5 to Group 6, it ultimately stabilized in Group 10 (Industrialized diversified middle-income), where it increased its income but struggled to attain significant industrial depth and export complexity.
While the East Asian Manufacturing-Concentration path could, in theory, lead to Group 19 (Highly industrialized complex high-income), by 2019, no country pursuing this route had attained high-income status. The highest observed GNI per capita within this group was USD 10,128 in China, which falls short of the USD 16,875 threshold. As of 2019, Group 6 had no remaining members as all five East Asian economies had surpassed it, and no new entrants emerged; only Myanmar remained in Group 5, leaving Myanmar as the only candidate to advance along this trajectory. Collectively, these observations suggest that from 1970 to 2019, the East Asian manufacturing-concentration pathway exhibited limited participation and showed restricted near-term potential for transitions to high-income status.
Figure 5 illustrates the resource-export-led path, in which countries achieved income gains with limited structural change (See
Appendix C,
Table A9). This pattern has exhibited consistency both before and after 1990. Typically, economies progress from Group 1 (non-industrial low-income) to Group 7 (non-industrial resource-dependent middle income) upon surpassing a Gross National Income (GNI) per capita threshold of USD 2186. Prior to 1990, three nations achieved this upward transition, while six countries accomplished it in the years that followed. Notably, after 1990, certain economies categorized as Group 3 (Industrialized resource-dependent low-income) also ascended to Group 7, reaching middle-income status despite an accompanying contraction in their manufacturing share in GDP. Thus, along the resource-led path, income gains often occurred without commensurate structural change and sometimes alongside erosion of manufacturing capacity.
The sustainability of this pathway proved fragile; three countries have transitioned from Group 7 back to either Group 1 due to income declines that fell below USD 2186. A notable example is Côte d’Ivoire, which recorded a GNI per capita of USD 2538 in 1970, yet fell below the middle-income threshold by 1985. By 1996, its GNI per capita had significantly dropped to USD 844, and by 2019, it had only partially recovered to USD 2036, still below its 1970 level.
Advancement from Group 7 (non-industrial resource-dependent middle-income) to high-income status is theoretically achievable; however, no country within our sample has made this transition directly. The observed upward trajectory consistently necessitated entry into Group 9 (industrialized resource-dependent middle income), which occurs when the manufacturing sector reaches at least 13.2% of GDP. This transition occurred twice before 1990 and four times subsequently.
Upon entering Group 9, the most common progression involved diversification, which required reducing resource dependence below 59.6% to access Group 10 (industrialized diversified middle income). In certain instances, countries further elevated their export sophistication to at least 37% to enter Group 11 (industrialized complex middle income). Mexico and Costa Rica are notable examples of this sequence, having advanced from Group 9 to Group 10 and subsequently to Group 11. Theoretically this route could continue to high-income, for example via transitions into Group 16 or Group 18. However, within our 1970–2019 window, no country that diversified out of the resource-led path reached high-income status.
A less common trajectory involved reaching high income without reducing resource dependence. Trinidad and Tobago moved from Group 9 to Group 17 (industrialized resource-rich high-income) between 1970 and 2010, with GNI per capita rising from USD 5554 to about USD 16,966, just above the USD 16,875 threshold, despite limited structural transformation. Notably, several major resource exporters were already classified as high-income in 1970, and their prior advancements fall outside the 1970–2019 timeframe and hence are not included in these figures.
Among high-income resource exporters, deindustrialization manifests as a shift from Group 17 (industrialized resource-rich high-income) to Group 15 (deindustrialized resource-rich high-income), as manufacturing activities decline below 14.7 percent of GDP. This trend mirrors the late-stage progression observed in high-income economies that follow manufacturing-led development, where a decline below roughly 23.6 percent indicates a transition from Group 19 to Group 18. However, this transition occurs at a lower level of manufacturing since no resource-rich country in our sample achieved the 23.6 percent threshold. Norway transitioned from Group 17 to Group 15 in 1982, and after 1990, Australia, Iceland, and New Zealand followed suit. By 2019, only Trinidad and Tobago and Bahrain remained in Group 17.
The findings reveal that, since 1990, the development trajectory centered on manufacturing has undergone significant reorganization. Initial industrialization no longer reliably leads to achieving middle-income status; instead, the deep-industrialization sequence from Group 10 to Group 13 to Group 14 has become increasingly rare. This has largely been supplanted by a moderate-intensity pathway towards higher export complexity, represented by Group 11. In the high-income tier, the trend of deindustrialization has intensified, becoming a common phenomenon post-1990. Economies have maintained complex export profiles while experiencing reduced manufacturing shares, resulting in reclassifications from Group 19 to Group 18, and, more frequently after 1990, into Group 16.
In contrast, the resource-export trajectory has shown little change: countries have continued to advance to Group 7, achieving income gains without significant structural transformation. Notably, with the exception of Trinidad and Tobago, which reached high income through an industrialized resource-dependent pathway (moving from Group 9 to Group 17), there have been no new high-income cases along this trajectory within our 1970–2019 timeframe. The discussion section contextualizes these patterns within the literature on premature deindustrialization and the fragmentation of global value chains.