Development, test-retest reliability and validity of the Pharmacy Value-Added Services Questionnaire (PVASQ)

Keywords: Pharmaceutical Services, Health Knowledge, Attitudes, Practice, Validation Studies as Topic, Questionnaires, Malaysia


Objective: (i) To develop the Pharmacy Value-Added Services Questionnaire (PVASQ) using emerging themes generated from interviews. (ii) To establish reliability and validity of questionnaire instrument.

Methods: Using an extended Theory of Planned Behavior as the theoretical model, face-to-face interviews generated salient beliefs of pharmacy value-added services. The PVASQ was constructed initially in English incorporating important themes and later translated into the Malay language with forward and backward translation. Intention (INT) to adopt pharmacy value-added services is predicted by attitudes (ATT), subjective norms (SN), perceived behavioral control (PBC), knowledge and expectations. Using a 7-point Likert-type scale and a dichotomous scale, test-retest reliability (N=25) was assessed by administrating the questionnaire instrument twice at an interval of one week apart. Internal consistency was measured by Cronbach’s alpha and construct validity between two administrations was assessed using the kappa statistic and the intraclass correlation coefficient (ICC). Confirmatory Factor Analysis, CFA (N=410) was conducted to assess construct validity of the PVASQ.

Results: The kappa coefficients indicate a moderate to almost perfect strength of agreement between test and retest. The ICC for all scales tested for intra-rater (test-retest) reliability was good. The overall Cronbach’ s alpha (N=25) is 0.912 and 0.908 for the two time points. The result of CFA (N=410) showed most items loaded strongly and correctly into corresponding factors. Only one item was eliminated.

Conclusions: This study is the first to develop and establish the reliability and validity of the Pharmacy Value-Added Services Questionnaire instrument using the Theory of Planned Behavior as the theoretical model. The translated Malay language version of PVASQ is reliable and valid to predict Malaysian patients’ intention to adopt pharmacy value-added services to collect partial medicine supply.


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Author Biographies

Christine L. Tan
Christine is an MSc candidate in Social Pharmacy at Universiti Sains Malaysia.
Mohamed A. Hassali
Prof. Azmi is Professor of Social Pharmacy at Universiti Sains Malaysia. He has published in international journals such as Social Science and Medicine, Research in Social and Administrative Pharmacy and Health Expectations.
Fahad Saleem
Dr. Fahad is Senior Lecturer at Universiti Sains Malaysia specializing in Social and Administrative Pharmacy. He has published in Health Expectations and Pharmacy Practice among others.
Hisham Aljadhey
Prof. Hisham is Dean at the College of Pharmacy, King Saud University.
Vincent B. Gan
Vincent has recently completed his PhD in Finance at Putra Business School. His first degree is in Pharmacy. He is skilled in all forms of quantitative and theoretical research in both finance and social pharmacy.


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