Changes in version 0.1.2 (2026-02-05) - Bootstrap replicate evaluation backend is now configurable via options(nmar.bootstrap_apply = "auto"|"base"|"future"). Default bootstrap behavior (nmar.bootstrap_apply = "auto") uses base::lapply() unless the current future plan has more than one worker; if so, it uses future.apply::future_lapply(future.seed = TRUE) when available. - Exptilt validation now rejects non-finite values (e.g., Inf, -Inf) in covariates (and non-finite observed outcomes). Changes in version 0.1.1 (2026-01-16) - CRAN release-related fixes - Fix return roxygen keyword in S3 Functions - Add research doi references to DESCRIPTION file Changes in version 0.1.0 Initial CRAN Release - First release of the NMAR package for estimating nonignorable nonresponse (NMAR) bias in survey data. Methods - Empirical Likelihood (EL): Added el_engine() implementing the estimator of Qin, Leung, and Shao (2002). This method uses empirical likelihood weights satisfying response mechanism equations and auxiliary moment constraints. - Exponential Tilting (Parametric & Nonparametric): Included robust implementations for both microdata (exptilt_engine) and aggregated contingency tables (exptilt_nonparam_engine) based on Riddles, Kim, and Im (2016). Key Features - Unified API: All estimators are accessible via a single, consistent nmar() interface supporting standard formula syntax (e.g., Y ~ X | Z). - Complex Survey Support: Seamless integration with the survey package. nmar() accepts survey.design objects, automatically handling weights and stratification. - Variance Estimation: Robust bootstrapping (S3) implementation for standard errors and confidence intervals across all engines. - Diagnostics: Rich return objects including convergence statistics, Jacobian condition numbers, and detailed weight summaries. Major Changes - Refactored Architecture: The exptilt and el engines share a unified structural design, ensuring consistent behavior for controls, standardization, and error handling. - Standardization: Added standardize = TRUE argument to engines to improve numerical stability during optimization.