authors
Shem Otoi Sam

abstract
The study explores the role of gross national income (GNI) in the Human Development Index (HDI), a key measure of social progress tied to the Sustainable Development Goals. Using 2021 macroeconomic data from 170 countries, the analysis applies principal component analysis (PCA) and logistic regression to evaluate the relative contribution of HDI predictors: GNI, life expectancy (LE), and mean years of schooling (ME). Data underwent transformation and normalization to ensure accuracy. PCA results indicate that the first principal component (PC1), largely representing income, explains 41.8% of the total variance, with GNI having the strongest positive loading (0.660), while LE and ME load modestly and inversely. Logistic regression shows GNI declined 5.3 times, but ME and LE increased the likelihood of GNI growth by 2.2 and 4.7 times respectively, while population reduced it by 61%. The findings underscore GNI’s dominant role in HDI, urging global emphasis on income improvement to drive social progress.