[Development of an instrument to measure self-care agency for the chronic ill in later adulthood--the first step of development].

The purpose of this study was to develop the instrument to measure self-care agency for the Japanese chronic ill in later adulthood and to test reliability and validity of that. First, the Self-Care Agency instrument draft which consists of 56 items rated along a 5-point Likert scale was developed. This draft was based upon the work of Orem (1991) and qualitative data of the Japanese chronic patients. Second, reliability and validity of this instrument was tested. The instrument was reviewed by 5 expert nurses and 16 nursing researchers for content validity. And this instrument was reviewed by 19 Japanese chronic patients for face validity. By result of content validity and face validity, this draft was refined. Next, the internal consistency, stability, and construct validity of this refined instrument was tested. The internal consistency of the instrument, as measured by the Cronbach's alpha, was 0.90 for a sample of 200 Japanese chronic patients. This instrument had a test-retest coefficient of r = 0.86 for a sample of 104 Japanese chronic patients. Using factor analytic techniques, five subscales emerged. These subscales gave some agreement with subscales that had been obtained before factor analysis. Therefore, construct validity of the instrument was established in some degree. And the subscale 'get a valid support' which emerged in this instrument was reflect Japanese cultural factor. Reliability and validity of this instrument were obtained in some degree. Further, it is necessary to refine this instrument, considering this research result.