UNP Journal of Statistics and Data Science
Vol. 4 No. 3 (2026): UNP Journal of Statistics and Data Science

Comparison of Least Square Spline and Penalized Spline for Modeling Human Development Index Determinants

Dita Amelia (Universitas Airlangga)
Tyo Anugrah Putra (Universitas Airlangga)
Slavina (Universitas Airlangga)
Thareq Alexander Manggala Napitupulu (Universitas Airlangga)
Layyin Gisvira (Universitas Airlangga)
Nila Khoirun Naili Salam (Universitas Airlangga)



Article Info

Publish Date
31 Aug 2026

Abstract

The Human Development Index (HDI) is a key indicator of national and regional development and supports the achievement of the Sustainable Development Goals (SDGs), particularly Goal 1 (No Poverty) and Goal 4 (Quality Education). However, substantial disparities in HDI remain across Indonesia’s regencies and cities due to complex and nonlinear socioeconomic relationships that cannot always be captured by conventional parametric methods. This study analyzes the determinants of HDI in 514 regencies and cities in Indonesia in 2024 using nonparametric spline regression by comparing Penalized Spline and Least Square Spline estimators. The explanatory variables include mean years of schooling, labor force participation rate, percentage of senior-high-school graduates, and poverty rate. Secondary data from BPS were analyzed through spline basis construction, smoothing parameter selection using Generalized Cross Validation (GCV), parameter estimation, significance testing, and residual diagnostics. The results show that all predictors have nonlinear relationships with HDI. Mean years of schooling and the percentage of senior-high-school graduates positively affect HDI, whereas labor force participation and poverty rate have negative effects. The second-order Penalized Spline model with four knot points achieved the best performance, yielding the lowest GCV (5.388838), the lowest MSE (4.948574), and the highest adjusted R² (86.94%). Residual diagnostics confirmed normality and zero mean but indicated autocorrelation, suggesting spatial dependence. Overall, Penalized Spline regression provides a flexible and accurate approach for modeling HDI determinants and informing evidence-based regional development policy.

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Journal Info

Abbrev

ujsds

Publisher

Subject

Computer Science & IT Decision Sciences, Operations Research & Management Mathematics Social Sciences

Description

UNP Journal of Statistics and Data Science is an open access journal (e-journal) launched in 2022 by Department of Statistics, Faculty of Science and Mathematics, Universitas Negeri Padang. UJSDS publishes scientific articles on various aspects related to Statistics, Data Science, and its ...