CAUCHY: Jurnal Matematika Murni dan Aplikasi
Vol 11, No 2 (2026): CAUCHY: JURNAL MATEMATIKA MURNI DAN APLIKASI

Panel Data Break the Diagnostics of Geographically Weighted Regression: Five Failures, Their Repair, and a Rice-Productivity Application in Indonesia

Rahmawati Tri Iriani (Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Surabaya, Indonesia)
Danang Ariyanto (Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Surabaya, Indonesia)



Article Info

Publish Date
30 Nov 2026

Abstract

Geographically weighted panel regression (GWPR) is assembled from cross-sectional tools. Five of them fail on a balanced panel whose units keep their coordinates over time. Each failure is stated as a proposition, derived in closed form, and repaired. An adaptive bandwidth in rows is not identified. A fold that holds out a whole unit cannot score a fixed-effects model without a plug-in level. A grid counted in units saturates at the inner training size, where its tie rule picks the bandwidth. A local and a global model share one information criterion only through a composite smoother. The BreuschPagan statistic reduces to a constant set by the sample size. The repairs are applied to 272 province-years, comprising 34 Indonesian provinces from 2018 to 2025, with log yield as the outcome. Under nested leave-one-province-out cross-validation, the global two-way fixed-effects model attains a cross-validated R2 of 0.100 and the GWPR 0.064. The GWPR loses in every variant tried. A province-block permutation test cannot distinguish Indonesia's real map from a random relabelling, and none of the 136 local slopes differs from its global counterpart. The R2 of 0.9997 in the earlier version of this study comes from the accounting identity between production and harvested area.

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Journal Info

Abbrev

Math

Publisher

Subject

Mathematics

Description

Jurnal CAUCHY secara berkala terbit dua (2) kali dalam setahun. Redaksi menerima tulisan ilmiah hasil penelitian, kajian kepustakaan, analisis dan pemecahan permasalahan di bidang Matematika (Aljabar, Analisis, Statistika, Komputasi, dan Terapan). Naskah yang diterima akan dikilas (review) oleh ...