Developing a context-based performance measure for persons with schizophrenia: the test of grocery shopping skills

This article describes how authenticity and directness, desired characteristics of performance measures, were applied to the development of a context-based Test of Grocery Shopping Skills (TOGSS) for persons with schizophrenia.

The steps used in developing the measure included interviewing consumers with schizophrenia to identify issues in grocery shopping, conceptualizing how authenticity and directness could be applied to shopping performance, and selecting grocery items to be used in the test. The two forms of the TOGSS were administered to 26 persons with schizophrenia or schizoaffective disorders to evaluate reliability (stability, equivalence, interrater) and validity (convergent, generalizability) of the TOGSS.

The correlations between the two forms of the TOGSS over two different testing periods were significant, ranging from .64 to .83. Subscale scores were moderately correlated (R = .52 to .94) with a similarly constructed test of drugstore shopping.

A systematic method can be used to develop a context measure of performance. The TOGSS has beginning evidence of reliability and validity. With further study, the test will be useful in assessing the independent living skill of grocery shopping in persons with psychiatric disorders.