Survey Weight Diagnostic Tests

Provides diagnostic tests for assessing the informativeness of survey weights in regression models. Implements difference-in-coefficients tests (Hausman 1978 ; Pfeffermann 1993 ), weight-association tests (DuMouchel and Duncan 1983 ; Pfeffermann and Sverchkov 1999 < https://www.jstor.org/stable/25051118>; Pfeffermann and Sverchkov 2003 ; Wu and Fuller 2005 < https://www.jstor.org/stable/27590461>), estimating equations tests (Pfeffermann and Sverchkov 2003 ), and non-parametric permutation tests. Includes simulation utilities replicating Wang et al. (2023 ) and extensions.