Gridsampler – A Simulation Tool to Determine the Required Sample Size for Repertory Grid Studies

Abstract

The repertory grid is a psychological data collection technique that is used to elicit qualitative data in the form of attributes as well as quantitative ratings. A common approach for evaluating multiple repertory grid data is sorting the elicited bipolar attributes (so called constructs) into mutually exclusive categories by means of content analysis. An important question when planning this type of study is determining the sample size needed to a) discover all attribute categories relevant to the field and b) yield a predefined minimal number of attributes per category. For most applied researchers who collect multiple repertory grid data, programming a numeric simulation to answer these questions is not feasible. The gridsampler software facilitates determining the required sample size by providing a GUI for conducting the necessary numerical simulations. Researchers can supply a set of parameters suitable for the specific research situation, determine the required sample size, and easily explore the effects of changes in the parameter set.

The spreading of the invasive sacred ibis in Italy

“…Because sampling bias is frequently present in occurrence records 48 , we removed some of the bias by subsampling records. To reduce the overfit in oversampled areas, we rarefied the observations collected in nearby localities using the gridsampler package 56 in R. We selected only one record for each cell in a grid 0.02 × 0.02 degrees (about 2.2 × 2.2 km). The records utilized in the model dropped from 10,260 to 1252 observations.…”

Rep:grid Software Supported Visualization of a Corporate Culture

“…For this study software that supported repertory grid interviews (RGI) were chosen. Originating from a clinical context in psychology RGIs have developed into an application technique in various research areas, including organizational behavior and corporate culture [9]. Distinct to seldomly quantitative questionnaires or qualitative interviews RGIs produce simultaneously qualitative statements which are quantitatively evaluated by the interviewee.…”

“…These elements are presented to the interviewee to carry out an elicitation process. The RGI technique records the bipolar constructs in a data matrix which allows carrying out statistical and mathematical calculations on the peculiarity of values and norms [9].…”

“…Content analysis attempts to group features into the same category with a common meaning. The groups themselves can be predefined (which was not the case in this repertory grid study) or from the list of elicited construct obtained inductively [9].…”

“…Consequently, the two main aims of the interviews and content analysis have to be considered. First, the researcher wants to cover the majority of the research domains inherent topics [9]. These are the clusters that are created by the combination of mathematical and content analysis.…”