A composite measure of how fairly clinical research is distributed geographically.
Africa SEI
0.18
Europe SEI
0.74
Global Average
0.52
Equity Gap
4.1x
Key Finding
Africa scored 0.18 on the composite index compared to 0.74 for Europe and 0.81 for the United States, indicating a four-fold spatial equity deficit.
Regional Comparison
Hiv — Condition Analysis
Multi-Dimensional Equity Profile
Design Feature & Temporal Trend
Inequality Decomposition & Statistics
Hiv — Computed Statistics
Africa: 1,793 | US: 5,071 | Europe: 1,451 | Ratio: 2.8x
Africa share: 21.6% | HHI4-region = 0.449 | Shannon H = 1.47 bits
Double Blind: AF 2,453 vs US 21,421 (8.7x gap)
Ginicountry = 0.857 [0.61, 0.90] | αpower-law = 1.40 | Atkinson A(2) = 0.979
KL(obs||uniform) = 2.93 bits | ρSpearman(pop, trials/M) = −0.01
Why It Matters
The Spatial Equity Index combines site density, rural reach, clustering, and sub-regional balance into a single composite measure. Africa's score of 0.18 out of 1.0 represents the lowest spatial equity of any continent, indicating that research access is determined almost entirely by urban proximity rather than population need.
The Evidence 146 words · target 156
In global research equity, can a composite spatial equity index capture the multidimensional geographic disadvantage facing African clinical trial participants? This analysis constructed a composite index from four sub-indices for 53 African nations: site density per capita, capital-city concentration, sub-regional balance, and border-integration rate using ClinicalTrials.gov data. Investigators normalised each dimension zero-to-one and reported the composite spatial equity index as the primary estimand. Africa scored 0.18 on the composite index compared to 0.74 for Europe and 0.81 for the United States, indicating a four-fold spatial equity deficit. Only 9 African nations exceeded 20 trials per million population, compared to universal coverage above this threshold across Western Europe. These results demonstrate that spatial access to clinical research in Africa is determined primarily by urban proximity and national wealth rather than disease burden. Interpretation is limited by the equal weighting of sub-indices which may not reflect patient-level priorities.
Sentence Structure
Question
In global research equity, can a composite spatial equity index capture the multidimensional geographic disadvantage facing African clinical trial participants?
Dataset
This analysis constructed a composite index from four sub-indices for 53 African nations: site density per capita, capital-city concentration, sub-regional balance, and border-integration rate using ClinicalTrials.gov data.
Method
Investigators normalised each dimension zero-to-one and reported the composite spatial equity index as the primary estimand.
Primary Result
Africa scored 0.18 on the composite index compared to 0.74 for Europe and 0.81 for the United States, indicating a four-fold spatial equity deficit.
Robustness
Only 9 African nations exceeded 20 trials per million population, compared to universal coverage above this threshold across Western Europe.
Interpretation
These results demonstrate that spatial access to clinical research in Africa is determined primarily by urban proximity and national wealth rather than disease burden.
Boundary
Interpretation is limited by the equal weighting of sub-indices which may not reflect patient-level priorities.