The QuestionPro discrete choice module (DCM) provides a range of options to the researcher for carrying out discrete choice conjoint research. One of the options specifies the design used by the DCM.
The design of a discrete choice question is the specification of how the respondent is presented the various levels of attributes in the survey. In discrete choice questions respondents are presented with sets of profiles of possible products or services and asked to select one of them. The configuration of the different choices, and how many are presented is referred to as the design of the discrete choice task. A good design will select specific configurations in a way such that the range of possible configurations is sampled in an efficient way. Designs are an optimization of the attribute levels available, they are an attempt, given various limitations, to select the best configurations of levels to give the most accurate results. The d-optimal design algorithm is therefore an attempt to best use the available respondents.
Optimal designs are a class of experimental designs that are optimal with respect to some statistical criterion. In the design of experiments for estimating statistical models, optimal designs allow parameters to be estimated without bias and with minimum-variance. A non-optimal design requires a greater number of experimental runs to estimate the parameters with the same precision as an optimal design. In practical terms, optimal experiments can reduce the costs of experimentation.
Conjoint Analysis D-Optimal Design is a design based on D-Optimality for the Conjoint Analysis (Discrete Choice) question. In general, D-Optimality is a concept that uses a desired set of experiments to optimize or investigate a studied object. It seeks to minimize |(X'X)−1|, or equivalently maximize the determinant of the information matrix X'X of the design.
Version:The first column in the spreadsheet is about the version number of the designs. Multiple versions get displayed randomly to the respondents. This number should be '0' if the particular row is about a fixed task. Task:The second column is the task number i.e. the group of options displayed at a time on the screen. Concept:The third column is the concepts number within each task. The columns after this will depend upon the number of features you have in the question - one column per feature.