Development and validation of the patient evaluation scale (PES) for primary health care in Nigeria

Background: Questionnaires developed for patient evaluation of the quality of primary care are often focussed on primary care systems in developed countries. Aim: To report the development and validation of the patient evaluation scale (PES) designed for use in the Nigerian primary health care context. Methods: An iterative process was used to develop and validate the questionnaire using patients attending 28 primary health centres across eight states in Nigeria. The development involved literature review, patient interviews, expert reviews, cognitive testing with patients and waves of quantitative cross-sectional surveys. The questionnaire's content validity, internal structures, acceptability, reliability and construct validity are reported. Findings: The full and shortened version of PES with 27 and 18 items, respectively, were developed through these process. The low item non-response from the serial cross-sectional surveys depicts questionnaire's acceptability among the local population. PES-short form (SF) has Cronbach's a of 0.87 and three domains (codenamed ` facility', 'organisation' and 'health care') with Cronbach's as of 0.78, 0.79 and 0.81, respectively. Items in the multi-dimensional questionnaire demonstrated adequate convergent and discriminant properties. PES-SF scores show significant positive correlation with scores of the full PES and also discriminated population groups in support of a priori hypotheses. Conclusion: The PES and PES-SF contain items that are relevant to the needs of patients in Nigeria. The good measurement properties of the questionnaire demonstrates its potential usefulness for patient-focussed quality improvement activities in Nigeria. There is still need to translate these questionnaires into major languages in Nigeria and assess their validity against external quality criteria.