Marilyn M. Schapira|Cindy M. Walker|Sonya K. Sedivy
Evaluating existing measures of health numeracy using item response theory
evaluate existing measures health numeracy using item response theory irta crosssectional study conducted participants completed assessments health numeracy measures including lipkus expanded health numeracy scale lipkus medical data interpretation test mdit lipkus mdit scaled irt utilizing twoparameter logistic modelthreehundred fiftynine 359 participants surveyed classical test theory parameters irt scaling parameters numeracy measures found items least moderately discriminating modified versions lipkus mdit scaled eliminating items low discrimination high difficulty parameters poor model fit modified versions demonstrated good range discrimination difficulty indicated test information functionsan irt analysis lipkus mdit indicate health numeracy scales discriminate well across range abilityhealth numeracy skills needed order patients successfully participate medical care accurate assessment health numeracy may help health care providers tailor patient education interventions patients level understanding ability item response theory scaling methods used evaluate discrimination difficulty individual items well overall assessment