Pharm World Sci
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Medicines information services (MISs) aim to promote the safe, effective and economic use of medicines. Results from published studies suggest that they provide effective information, which in many cases results in improved patient outcome. However, there are several methodological issues that are important in the interpretation of such studies. ⋯ Most studies have been conducted in the United States. Various methodological considerations were identified: study design, sampling, data collection, choice of outcome measures, and validity. The results of each study are interpreted in view of the methods used. In addition, the implications of the methods selected on the validity, reliability and generalisability of the results are discussed. Finally, suggestions for future studies are provided, in order to maximise validity and reliability.