[23, 26] Experimental design methods can help reduce this number by creating smaller fractional factorial designs, e.g. orthogonal designs. These designs enable the estimation of main effects, i.e. the effect of each

Enzalutamide cell line independent variable on the dependent variable, as well as possible interactions, i.e. when preferences for one attribute depend on the level of another.[30] Orthogonal designs can be obtained from design catalogues, statistical software programs or websites and have the properties of orthogonality (where attributes are statistically independent of each other) and level balance (where levels of attributes appear an equal number of times).[30] Following the development of the experimental design, choice sets need to be constructed, especially PD0325901 cost when two or more alternatives are present. The development of

the experimental design is followed by the designing of the DCE questionnaire, pilot testing and data collection. Following administration of DCE questionnaires and data collection, the next step is discrete choice modelling within a RU framework to analyse the responses obtained from the DCEs. The included articles were reviewed and individual details of the DCE methodological steps utilised (including the number of attributes, type of attributes, design type, design plan, design source, method of constructing choice sets, mode of administration of questionnaire, estimation method used and validity tests) were identified

and reported. The included studies were then evaluated for their application within the field of pharmacy with respect to the focus of preference (patient, provider, both), focus of study, attributes used, key findings and conclusions. Each paper was also assessed using a ‘checklist of factors to be considered when conducting a DCE’ adapted from Lancsar and Louviere.[25] Please refer aminophylline to Figure 2 for more details. The search generated 243 possible articles. After elimination of duplicates and screening as per inclusion/exclusion criteria (Figure 3),[34] 12 studies were retrieved which were included in the review.[35-46] Table 1 summarises the background of DCE studies reviewed. The majority of the pharmacy-related DCE studies were conducted in the UK and almost all the studies were published in the last decade, of which 10 were published after 2005. Studies elicited patient preferences or pharmacist preferences or preferences of both for various pharmacy-related products and services. There were no studies that incorporated DCEs into a decision-making framework to inform pharmacy policy. The reviewed studies were examined for the different DCE stages conducted and the results have been reported in Table 2. Table 2 shows the current trends with respect to attribute and level selection within the pharmacy context.