Psychometric evaluation of the Employer Support for Breastfeeding Questionnaire (ESBQ).

The purpose of this descriptive methodological study was to develop and evaluate the psychometric properties of the Employer's Support for Breastfeeding Questionnaire (ESBQ). The convenience sample consisted of 380 business owners, managers, or supervisors from the Midwestern United States. Data were collected using Web and paper-based questionnaires from January to March 2008. Psychometric evaluation included item analysis, scale reliability, and construct validity. The ESBQ subscales had Cronbach's alphas ranging from 0.85 to 0.92. Most inter-item and item-to-total correlations were above the recommendation of 0.30. The test-retest reliability of each subscale ranged from 0.93 to 1.0. Confirmatory factor analysis supported the construct validity of the scale. The comparative fit index (CFI) and the non-normal fit index (NNFI) were 0.90 and 0.91, respectively, and the root mean square error of approximation (RMSEA) was 0.05. Findings supported the ESBQ as reliable, valid, and theoretically consistent with the theory of planned behavior.