Questionnaires are one of the most widely used means of collecting data. Self-administered questionnaires are used widely in research as they offer an efficient and cost effective means of collecting data in large target groups. Problems with rates of questionnaire return can pose serious problems for researchers. The issue of overall response rates to questionnaires has been the subject of research and there is now a substantial amount of empirical evidence around interventions aimed at maximising the return of questionnaires that have been distributed for research purposes (Nakash et al, 2006; Edwards et al, 2009). However, the successful return of self-administered questionnaires does not ensure that the information collected is always complete or as complete as is possible. In addition to the response rates to questionnaires, researchers ought also to be concerned about the completeness of responses to those questionnaires. There are limited empirical studies looking exclusively at methods that might improve the quality and quantity of the data collected by questionnaires despite recommendations for such studies over a number of years (Jenkins & Dillman, 1995;
Cavusgil & Elvey-Kirk, 1998; De Leeuw, 2001; Wilks et al, 2007; Edwards et al, 2009; Edwards 2010). Questionnaires are used widely and will continue to be used widely in many types of research, including outcome measurement using scales. It is therefore essential that those questionnaires be designed to be robust, efficient research instruments. Identifying evidence-based interventions to improve the completeness of response to items in self-administered questionnaires would enhance the ability of researchers to design questionnaires that will collect complete, appropriate and accurate data. This relevant, timely and important review will provide researchers, both Irish and international, with the much-needed empirical evidence
necessary to guide the design and construction of research questionnaires to enhance the completeness of response to the questionnaires. This will improve the quality and quantity of data collected by questionnaires and so has the potential to improve the quality of many types of research studies including clinical trials.
