3.1. Empirical Evidence of Volatility in SDG Performance
Progress towards the SDGs remains highly uneven across countries. Despite their universal framing, SDGs trajectories exhibit persistent stratification. Many countries stagnate or regress on key goals, particularly those related to inequality, institutional performance, and climate action, whilst others advance more consistently. This heterogeneity suggests that developmental processes may follow distinct structural pathways rather than converging linearly toward uniform outcomes.
In addition to variation in SDG achievement levels, we document substantial differences in intertemporal volatility. To capture this, we compute the coefficient of variation (CV) for each country across the 15 SDGs over the 2019–2024 period. The distribution of average volatility is broad: some countries exhibit consistently stable trajectories, whereas others experience substantial year-on-year fluctuations. Crucially, these volatility patterns are not well explained by standard development classifications, such as income group or geographic region.
Figure 1 illustrates this heterogeneity by presenting the 30 most volatile and the 30 most stable countries, based on their average coefficient of variation. High-income and low-income countries are present in both groups, indicating that volatility is not monotonically related to income or institutional capacity. The presence of economically diverse nations in both extremes challenges conventional assumptions about the relationship between development level and policy stability.
Figure 2 maps the global distribution of volatility. Geographic clustering is visible but does not align cleanly with income levels or institutional classifications, reinforcing the notion that more complex or latent structures drive volatility patterns. Notably, regions traditionally considered developmentally similar exhibit substantial internal variation, suggesting that country-specific structural features may play a more decisive role than regional or income-based groupings.
We also observe substantial heterogeneity across goals; some SDGs are systematically more volatile across countries, particularly those related to governance, climate action, and inequality. By contrast, goals related to health and education tend to be more stable. This pattern suggests that certain policy domains are inherently more volatile, potentially reflecting their sensitivity to external shocks, political cycles, or institutional fragility.
Figure 3 presents average CVs by goal. Industry, innovation and infrastructure (Goal 9) and no poverty (Goal 1) are the most volatile, whereas responsible consumption and production (Goal 12) and decent work and economic growth (Goal 8) are the most stable.
Perhaps most striking is the presence of country pairs that, despite apparent differences in income and institutional development, exhibit nearly identical volatility patterns. For example, Australia and Ukraine, India and Uganda, and Morocco and Haiti all display comparable average CV levels across SDGs, despite being situated in different regions and development tiers. This convergence in volatility profiles across structurally dissimilar countries provides further evidence that volatility reflects latent structural features of national development processes that are not captured by conventional classifications.
Figure 4 shows SDG volatility profiles for these illustrative country pairs. The similarity of patterns—despite differences in income levels, regional context, and governance structures—supports the hypothesis that volatility is shaped by deeper structural configurations that transcend surface-level economic or institutional indicators. These findings motivate the use of data-driven methods to identify latent development regimes based on actual goal-level dynamics.
Beyond variation at the country level, we observe systematic differences in volatility across both goals and structural groupings. To examine this, we calculate the average coefficient of variation for each SDG goal, disaggregated by region and income group.
Figure 5 and
Figure 6 summarise these results, revealing both expected and surprising patterns in the distribution of development volatility.
Figure 5 displays regional volatility profiles. Sub-Saharan Africa exhibits consistently high volatility across most goals, particularly in the goals of no poverty (Goal 1), quality education (Goal 4), and climate action (Goal 13). Asia and Latin America also exhibit elevated CVs in several key goals, reflecting ongoing structural transitions and exposure to external shocks. By contrast, Europe and North America demonstrate more stable goal-level dynamics, with only isolated peaks in specific domains. These patterns suggest that regional context conditions not only average SDG achievement, but also the stability of progress over time.
Figure 6 reports the decomposition by World Bank income groups. As expected, low-income countries tend to experience greater volatility across goals, reflecting institutional and financial constraints. However, the relationship is non-monotonic. Some lower-middle-income countries exhibit greater volatility than their low-income peers, particularly in industrial and environmental goals (e.g., Goals 9 and 13). Similarly, the high-income group shows substantial volatility in select goals, suggesting that income alone does not determine stability. This non-linearity underscores the limitations of income-based classifications in capturing the full complexity of development dynamics.
Together, these results reinforce the central argument: development volatility is not random noise, but reflects persistent structural asymmetries that are not reducible to income group or region. This motivates a more flexible empirical framework in which latent developmental regimes are derived from actual goal-level dynamics rather than imposed exogenously. The heterogeneity documented here points to the need for typologies that accommodate both average performance and volatility as defining features of sustainable development trajectories. The following sections employ latent class analysis to identify such regimes and examine their structural determinants. Detailed volatility statistics disaggregated by income group and geographic region are provided in
Table A5 and
Table A6 (
Appendix B).
3.2. Identifying Latent Development Regimes
To identify latent structures in SDG performance, we employed Latent Class Analysis (LCA), a model-based clustering technique that probabilistically assigns countries to unobserved groups based on their SDG profiles. We estimated competing specifications with two to five classes using 2019 data and evaluated model fit using log-likelihood, information criteria (AIC, BIC), entropy, and substantive interpretability.
Table 1 presents the fit statistics for all candidate models.
Whilst the five-class solution yielded the lowest AIC and BIC values, we retained the three-class specification for substantive and methodological reasons. First, a three-class typology aligns with established conceptual frameworks in development studies, which often distinguish between leading, transitional, and lagging country groups, thereby enhancing interpretability and policy relevance. Second, although models with more classes may improve statistical fit, they risk overfitting, reducing generalisability and obscuring substantive meaning. Third, increasing class numbers in panel settings introduces considerable estimation complexity, amplifying convergence problems and uncertainty in class assignment. Finally, our preliminary empirical review indicated that the three-class solution effectively captured essential cross-country differences, whilst adding more classes fragmented the patterns without yielding meaningful distinctions.
This three-class structure was applied annually to the full panel (2019–2024), assuming temporal consistency in the underlying grouping logic. Notably, the classes naturally aligned with meaningful differences in SDG achievement levels across countries: Class 1 comprised countries with the lowest overall SDG performance (lagging regime), Class 2 represented countries with moderate SDG performance (transitional regime), and Class 3 comprised countries with the highest SDG performance (leading regime).
To evaluate the stability and coherence of the latent class structure, we visualised the mean values of each SDG score across the 15 goals by latent class and year.
Figure 7 presents radar plots illustrating the multidimensional SDG profiles for each class across the 2019–2024 period. These plots reveal a stable and internally coherent structure of latent classes, each representing a distinct development regime.
Class 3 consistently demonstrates the highest levels of SDG achievement, forming a broad and symmetrical profile across years, indicative of balanced performance across economic, social, and environmental dimensions. Class 2 exhibits moderate outcomes, with systematic underperformance across inequality and institutional indicators. Class 1 lags on most SDGs, particularly in ecological and governance domains. The preservation of relative positioning and the parallelism in class-specific profiles over time suggest that these latent classes capture durable, structurally differentiated development regimes. The absence of convergence or substantive overlap across classes supports the interpretation of these groups as persistent and internally consistent. This empirical regularity justifies using class labels as stable identifiers in analysing regime-based differentiation in global development.
The three latent regimes identified through SDGs performance clustering exhibit marked heterogeneity along both geographical and developmental lines. Class 1 (lagging regime) includes 46 countries, predominantly low-income or lower-middle-income economies. This group spans Sub-Saharan Africa (e.g., Angola, Benin, Burkina Faso), parts of South Asia (e.g., Afghanistan), and several fragile or post-conflict states. These countries generally display low and volatile SDG scores, consistent with systemic development constraints.
Class 2 (transitional regime) is the largest, comprising 81 countries. It contains a highly diverse mix of upper-middle-income and some lower-middle-income countries, drawn from nearly all world regions. Examples include Algeria, Argentina, Albania, Armenia, and Azerbaijan. The heterogeneity of this class suggests that transitional SDG performance does not neatly align with geography or income group, but may reflect intermediate structural configurations that transcend conventional classifications.
Class 3 (leading regime) comprises 47 countries, primarily high-income and institutionally advanced economies, including Australia, Austria, Belgium, and Bahrain. Whilst the majority of these countries belong to the OECD or have advanced service-based economies, the presence of a few non-Western high performers (e.g., Brunei Darussalam, Chile) highlights the global diffusion of sustainability leadership beyond traditional Western blocs. Taken together, these class compositions underscore that latent SDG regimes cut across standard classifications. Countries with comparable economic output or geographic proximity often diverge in regime placement, reinforcing the need for empirical typologies over exogenous groupings.
To assess the dynamics of countries' movement across sustainability trajectories, we examine class transition patterns over time.
Figure 8 displays annual transition matrices that highlight how countries remained in or shifted between latent classes based on their SDG performance from 2019 to 2024. These matrices reveal the temporal stability of regime membership and the extent of cross-class mobility.
The transition matrices exhibit remarkable temporal stability in classifying countries based on their SDG performance. Most countries remained in their initial class over the six years, with particularly high persistence observed for Class 3, the highest-performing group. These countries experienced virtually no downward movement, reinforcing the notion of entrenched leadership in sustainable development. By contrast, limited mobility was observed between Classes 1 and 2, and occasionally from Class 3 to Class 2 between 2019 and 2022, possibly reflecting temporary regressions due to shocks or measurement fluctuations in specific goal domains. The overall persistence of the class structure confirms the structural robustness of the latent classification and highlights long-standing disparities in global progress towards the Sustainable Development Goals.
To further visualise the temporal stability and limited mobility across regimes,
Figure 9 presents an alluvial diagram tracking country movements between classes from 2019 to 2024. The width of each stream represents the number of countries moving between (or remaining within) Classes 1 (low), 2 (moderate), and 3 (high). The stability of most streams reflects strong temporal consistency in country groupings, with limited upward or downward transitions.
These findings suggest that most countries appear locked into lower-performance trajectories. To deepen the understanding of longitudinal mobility within the latent class structure, we document discrete country-level transitions across sustainability performance classes.
Table 2 provides a detailed account of all observed class shifts between 2019 and 2024, offering granular insight into the dynamics of SDG trajectory reclassification and highlighting critical cases of advancement, regression, and volatility.
The classification results reveal that most countries maintain stable regime membership over the observation period. However, a rare subset of transitions, although rare, suggests non-trivial mobility across latent SDG performance regimes. Bulgaria and Romania transitioned to higher-performing regimes during the latter part of the sample. These cases align with gradual structural adjustment, possibly linked to institutional consolidation or improvements in selected SDG domains. Although our model does not formally identify causal drivers, the persistence of the reclassification over consecutive years diminishes the likelihood of purely statistical noise.
Kuwait and Bahrain exhibit recurrent transitions between adjacent regimes (Class 2 and Class 3). This pattern may reflect proximity to the class boundary combined with indicator-level volatility, but it could also signal structural instability in underlying development factors. The absence of sustained directional movement suggests low regime inertia and warrants further investigation. Myanmar and the Syrian Arab Republic were reclassified into lower-performing regimes, temporally coinciding with episodes of political and institutional breakdown. Whilst the model abstracts from conflict and governance shocks, the timing of these downward shifts is consistent with broader macro-institutional disruption. These cases illustrate that latent regime structures are sensitive to exogenous structural shocks.
Overall, the presence of regime transitions, both upward and downward, supports the interpretation of regime membership as a dynamic rather than fixed classification. The remarkable stability of most countries within their initial classes, combined with isolated yet meaningful transitions, suggests that latent developmental regimes are persistent structural configurations that significant institutional or economic shocks can disrupt. These findings provide empirical support for treating SDG performance as governed by latent regime structures that are both durable and responsive to fundamental structural change.
3.3. Structural Anchoring of Development Regimes
To validate the substantive relevance of the latent classification, we examine whether countries assigned to different SDG performance clusters also differ systematically on a set of structural indicators not included in the latent class model. This external validation serves a dual purpose: it provides empirical justification for treating latent classes as meaningful development regimes, and it identifies which structural factors most strongly differentiate these regimes. We employ one-way analysis of variance (ANOVA) to test whether key demographic, technological, economic, and institutional indicators differ significantly across latent classes.
The analysis treats class membership as a grouping variable and each structural indicator as the outcome. Whilst this descriptive approach does not imply causality, it highlights whether the empirically derived classes correspond to observable structural differences. To ensure the reliability of results, we focus on variables with sufficient data coverage; those with more than 5% annual missingness were excluded to ensure comparability and statistical validity. For each variable-year combination, we report F-statistics, p-values, and Bonferroni-adjusted post-hoc comparisons to identify which specific class pairs differ significantly.
Table 3 presents the ANOVA results for selected structural variables across the 2019–2024 period. The analysis reveals consistent, statistically significant differences across latent classes for most indicators, with F-statistics ranging from moderate to exceptionally large. These findings confirm that the latent typology captures meaningful structural differentiation, rather than arbitrary or ephemeral groupings.
The results reveal striking and consistent structural differentiation across latent development regimes. Internet penetration emerges as one of the most powerful discriminators between classes, with exceptionally large F-statistics exceeding 1,500 across all years. The hierarchical ordering is unambiguous: Class 3 (leading regime) exhibits significantly higher internet access than Class 2 (transitional regime), which in turn surpasses Class 1 (lagging regime). This pattern persists across the entire observation period, with F-values actually increasing over time—from 1,512.6 in 2019 to 2,014.3 in 2023—suggesting that digital divides between development regimes are widening rather than converging. The consistency of this finding underscores the centrality of digital infrastructure and connectivity in contemporary development trajectories.
Government effectiveness displays an equally robust pattern of differentiation, with F-statistics ranging from 948.8 to 1,194.8 across years. As with digital access, the ordering is strictly monotonic: leading countries consistently outperform transitional countries, who in turn surpass lagging countries. The magnitude of these differences—reflected in effect sizes well above 0.8 standard deviations between classes—indicates that governance quality is not merely statistically significant but substantively profound. Bartlett tests for equal variances consistently fail to reject the null hypothesis (p > 0.05 for most years), suggesting that whilst mean governance levels differ dramatically across classes, the within-class variance remains relatively homogeneous. This implies that countries within the same latent regime share not only similar levels of institutional effectiveness but also comparable degrees of intra-regime heterogeneity.
Population growth exhibits more complex patterns. Whilst F-statistics remain highly significant (ranging from 115.5 to 299.1), the pairwise comparisons reveal non-monotonic relationships in some years. For instance, in 2019 and 2022, Classes 2 and 3 do not differ significantly from one another (p > 0.05), yet both differ substantially from Class 1. This suggests that demographic dynamics may follow a threshold pattern: once countries surpass a certain development threshold (i.e., transition from Class 1 to Class 2), population growth rates stabilise, and further advancement to Class 3 does not entail additional demographic shifts. The presence of significant Bartlett statistics (all p < 0.001) indicates substantial heterogeneity in variance, likely reflecting the diverse fertility transitions and migration patterns within latent classes.
Economic indicators display more modest, though still significant, differentiation. GDP growth rates in 2019 show a clear hierarchical pattern (F = 10.5, p < 0.001), with leading countries outperforming transitional and lagging countries. However, the relatively small F-statistic compared to governance or digital indicators suggests that short-term economic growth is less central to regime differentiation than structural institutional factors. Foreign direct investment (FDI) inflows display similar patterns, with Class 3 countries attracting significantly more investment than Classes 1 and 2, though Classes 1 and 2 themselves do not differ significantly. This reinforces the interpretation that certain structural advantages—such as institutional quality and digital infrastructure—act as magnets for capital, further entrenching developmental stratification.
Taken together, the ANOVA results provide compelling external validation for the latent class typology. The three empirically derived classes correspond to meaningful and persistent differences in structural conditions, with governance quality and digital access emerging as the most powerful discriminators. The stability of these patterns across years supports the interpretation that latent classes reflect durable developmental regimes, shaped by deep-seated institutional and technological configurations, rather than transient economic fluctuations. These findings set the stage for the subsequent regression analysis, which models class membership as a function of these structural predictors and quantifies the conditional probabilities of regime transitions.
Predictors of Regime Membership: Ordered Logistic Regression
Having established that latent development regimes exhibit systematic structural differentiation, we now model class membership as a function of these structural predictors. We employ ordered logistic regression, which appropriately captures the ordinal nature of class membership—from Class 1 (lagging regime) through Class 2 (transitional regime) to Class 3 (leading regime). This specification assumes proportional odds: the effect of each predictor on the log-odds of being in a higher class is constant across the class thresholds. We estimate two sets of models: year-specific models (2019–2024) to capture temporal variation in predictor effects, and a pooled model with year-fixed effects to identify robust, time-averaged associations.
Table 4 presents the year-specific ordered logit results. Each column represents a separate model estimated for a single year, allowing us to assess the temporal stability of structural effects. Coefficients are reported in log-odds units, with standard errors in parentheses. Positive coefficients indicate that higher values of the predictor increase the probability of belonging to a higher-performing class.
The year-specific models reveal striking consistency in the role of digital access. Internet penetration exhibits positive, highly significant coefficients across all years from 2019 to 2023, with magnitudes ranging from 0.111 (p < 0.001) in 2019 to 0.178 (p < 0.001) in 2023. This upward trend in coefficient magnitude suggests that the association between internet access and regime membership has intensified over time, possibly reflecting the growing centrality of digital infrastructure in contemporary development processes. The absence of significance in 2024 likely reflects limited data availability for that year, as evidenced by the substantially reduced sample size. These findings underscore that digital connectivity is not merely a correlate of development but an increasingly decisive structural factor shaping countries' positions within the global SDG hierarchy.
Government effectiveness displays similarly robust associations with regime membership. Coefficients remain large and highly significant across all years (ranging from 2.108 to 2.964, all p < 0.001), indicating that institutional quality exerts a profound and stable influence on SDG performance trajectories. The magnitude of these effects is substantively striking: a one-unit increase in government effectiveness—corresponding approximately to the difference between the 25th and 75th percentiles of the global distribution—is associated with a two- to threefold increase in the log-odds of belonging to a higher class. This persistence of institutional effects across years supports the hypothesis that governance quality represents a deep structural determinant of development regimes, rather than a transient or cyclical factor.
Public health investment shows consistent positive effects from 2019 to 2022, with coefficients ranging from 0.423 to 0.500 (all p < 0.05). However, the effect is not statistically significant in 2023 or 2024. This temporal pattern may reflect saturation dynamics: once health systems reach a threshold of investment, additional marginal spending may yield diminishing returns on overall SDG performance. Alternatively, the weakening effect in later years could signal structural disruptions associated with the COVID-19 pandemic and its aftermath, which may have complicated the relationship between health expenditure and broader development outcomes. These findings suggest that health investment plays a crucial role in regime differentiation during periods of relative stability but may exhibit threshold effects or contextual sensitivity during systemic shocks.
Population growth displays negative coefficients in most years, though statistical significance is intermittent. The negative association suggests that high demographic pressure may constrain countries' ability to advance to higher-performing regimes, consistent with theories emphasising resource scarcity and infrastructure strain in high-growth contexts. GDP growth, by contrast, shows inconsistent effects across years. The significant negative coefficient in 2023 (−0.188, p < 0.05) is counterintuitive. It may reflect short-term volatility or measurement issues, as growth rates in that year were influenced by post-pandemic recovery dynamics that varied widely across countries. The general lack of consistent significance for GDP growth aligns with the ANOVA findings, reinforcing the interpretation that structural and institutional factors—rather than short-term economic fluctuations—are the primary drivers of regime membership.
To identify robust, time-averaged effects, we estimate a pooled ordered logit model with year-fixed effects. This specification pools observations across the 2019–2024 period (N = 1,002) and includes dummy variables for each year to control for temporal variation. Missing covariate data were handled via multiple imputation by chained equations (m = 20). Model estimates were pooled across imputations using Rubin’s rules, and
Table 5 presents the pooled coefficients and standard errors.
The pooled model confirms the primacy of digital access and governance quality as drivers of regime membership. Internet penetration (β = 0.049, p < 0.001) and government effectiveness (β = 0.943, p < 0.001) remain highly significant, whilst health expenditure also achieves significance (β = 0.153, p = 0.004). These three variables emerge as the consistent, robust predictors of SDG regime placement. By contrast, political stability, GDP growth, FDI inflows, and energy-related indicators are not statistically significant in the pooled specification, suggesting that their effects are either context-specific or overshadowed by the dominant influence of institutions and digital infrastructure.
The year-fixed effects reveal a notable temporal pattern: coefficients for 2021, 2022, and 2023 are negative and significant relative to the 2019 baseline, whilst the 2024 coefficient is sharply negative (β = −2.99, p = 0.003). This pattern suggests that, holding structural conditions constant, the probability of belonging to higher-performing classes declined over the observation period. This temporal drift may reflect global disruptions associated with the COVID-19 pandemic and subsequent economic instability, which disproportionately affected countries' capacity to sustain progress on the SDGs. The strong negative effect in 2024, however, should be interpreted cautiously, given the limited availability of data for that year.