Introduction: Community-dwelling older adults often experience difficulties with IADLs, such as shopping, as they age and become disabled. However, no scale exists to assess IADL difficulties in detail. Shopping is a key factor in IADL decline. Using movement observation, we developed the Process Analysis Scale for Shopping in Community-Dwelling Older Adults (PASS-OA) to assess the process and difficulty level of shopping activities as motor function declines. The scale consists of 10 items and was designed to examine these difficulties in detail. We previously examined its content validity (Yuri et al., 2023).
Objectives: This study aimed to assess the concurrent validity of the PASS-OA.
Methods: Spearman's rank correlation coefficients were calculated for the PASS-OA total score, the Lawton IADL scale (Lawton), and the Frenchay Activity Index (FAI) total score. In addition, correlation coefficients were calculated for the PASS-OA total score and the ‘shopping’ sub-scores of both Lawton and FAI scales.
Results: The analyzed population consisted of 92 participants with a mean age of 82 years, and 68 (73.9%) were female. The total PASS-OA score showed a correlation of 0.32 with Lawton (p<0.001) and 0.41 with FAI (p<0.001). The correlation between the total PASS-OA score and Lawton’s ‘shopping’ score was 0.24(p<0.005), and FAI‘s ‘shopping’ score was 0.30(p<0.001).
Discussion: A weak correlation was found between the PASS-OA and the Lawton scale, and a positive correlation was observed between the PASS-OA and the FAI. The total PASS-OA scores and Lawton’s and FAI‘s ‘shopping’ scores were all weakly correlated.
Conclusion: As all correlations were statistically significant, PASS-OA was considered to likely have criterion-related validity.