SurveyNCD - Tools for Self-Reported Health Indicators in Complex Surveys

Provides tools for analysing population health survey data (WHO STEPS, DHS, MICS, and similar complex sample surveys), where chronic conditions are self-reported rather than ICD-coded and estimates must account for stratification, clustering, and sampling weights. Includes a self-reported multimorbidity index based on the Functional Comorbidity Index (Groll et al., 2005, <doi:10.1016/j.jclinepi.2004.10.018>), design-weighted population prevalence estimation via the 'survey' package, a survey-weighted concentration index for health inequality analysis, a DHS anthropometric z-score categoriser, a choropleth mapping helper, and exploratory survey-weighted gradient boosting (via 'xgboost') with SHAP-based explainability. The gradient boosting component applies case weights but does not yet propagate cluster and strata design effects into variance estimates; it should be treated as exploratory rather than as design-based inference.