Objective: This study aims to investigate the reliability and validity of Cognitive Impairment Screening (CIST). Methods: This study used the data of 321 people who responded to the CIST for older adults living in Seoul City. Analysis of this study First, the unidimensionality assumption and local independence were investigated through confirmatory factor analysis. Second, the partial credit model (PCM) among the Rash models was used to investigate the hierarchical structure of item fit and item difficulty. Thirdly, the differential items function was investigated to analyze differences between items due to individual characteristics. Finally, discriminant validity was confirmed using the CIST and depression screening tools (Patient Health Questionnaire-9; PHQ-9). Results: The mean age of the participant was 8048 (SD = 6.59) years, and there were 45 (14.02) males and 276 (85.98) females. Results of CIST analysis First, as a result of CIST's factor analysis, unidimensionality and local independence were assumed. Second, item fit through Rasch analysis was found to be fit for all six domains (0.6