The Gerontologist · May 22, 2026

Assessing the feasibility of linking Section G and Section GG measures of function in skilled nursing facilities

By Lam K, White EM, McConeghy KW et al.

BACKGROUND AND OBJECTIVES: In skilled nursing facilities (SNFs), Section GG replaced Section G as the instrument for measuring function in 2023. To inform how previously validated scales and scores derived from Section G items might be re-produced from Section GG items, we examined key measurement assumptions in both instruments. RESEARCH DESIGN AND METHODS: We identified 1,131,694 Minimum Data Set 3.0 assessments of unique persons with complete Sections GG and G between October 2018 and September 2023 across 2,200 SNFs in the Long-Term Care Data Cooperative. We examined: (i) assessment instructions, (ii) item-level Spearman's correlations, (iii) measures of fit and factor structure in confirmatory and exploratory factor analyses, and (iv) graded response item response theory parameters. RESULTS: Several Section GG items were conceptually similar and highly correlated (ρ ≥ 0.7). After removing redundant items, a combined scale of both instruments was not unidimensional in confirmatory factor analyses (Comparative Fit Index = 0.753, Tucker-Lewis Index = 0.724, root-mean-square error of approximation = 0.153) and items from each instrument generally loaded onto separate but correlated factors (inter-factor correlation 0.735) in exploratory factor analyses. In item response theory analyses, Section GG items better captured independence while Section G items better captured dependence. DISCUSSION AND IMPLICATIONS: Sections GG and G measure related yet distinct constructs, emphasizing the need for caution when interpreting a sum of Section GG items as a reflection of underlying health in SNF patients. Scales and scores derived from Section G items cannot be presumed to be equivalent when derived from Section GG items, and further work is needed examining interchangeability.

doi.org/10.1093/geront/gnag116Open access, accepted manuscriptPubMed 42172600Biomarkers