Linear linking for related traits (LLRT): A novel method for the harmonization of cognitive domains with no or few common items.

TitleLinear linking for related traits (LLRT): A novel method for the harmonization of cognitive domains with no or few common items.
Publication TypeJournal Article
Year of Publication2022
AuthorsNichols, EL, Cadar, D, Lee, J, Jones, RN, Gross, AL
JournalMethods
Volume204
Pagination179-188
ISSN Number1095-9130
KeywordsCognition, HCAP, Research Design
Abstract

Harmonization means to make data comparable. Recent efforts to generate comparable data on cognitive performance of older adults from many different countries around the world have presented challenges for direct comparison. Neuropsychological instruments vary in many respects, including language, administration techniques and cultural differences, which all present important obstacles to assumptions regarding the presence of linking items. Item response theory (IRT) methods have been previously used to harmonize cross-national data on cognition, but these methods rely on linking items to establish the shared metric. We introduce an alternative approach for linking cognitive performance across two (or more) groups when the fielded assessments contain no items that can be reasonably considered linking items: Linear Linking for Related Traits (LLRT). We demonstrate this methodological approach in a sample from a single United States study split by educational attainment, and in two sets of cross-national comparisons (United States to England, and United States to India). All data were collected as part of the Harmonized Cognitive Assessment Protocol (HCAP) and are publicly available. Our method relies upon strong assumptions, and we offer suggestions for how the method can be extended to relax those assumptions in future work.

DOI10.1016/j.ymeth.2021.11.011
Citation Key12665
PubMed ID34843977
PubMed Central IDPMC9133269
Grant ListU01 AG064948 / AG / NIA NIH HHS / United States
T32 AG000247 / AG / NIA NIH HHS / United States
U01 AG009740 / AG / NIA NIH HHS / United States
K01 AG050699 / AG / NIA NIH HHS / United States
U01 AG058499 / AG / NIA NIH HHS / United States
P30 AG066587 / AG / NIA NIH HHS / United States