LogRatio searches for outliers among questions and respondents, because outliers can impair the correct interpretation of survey data and, in some cases, it may be advisable to remove them.
When an outlier is detected LogRatio makes a comment in the PDF report.
Outliers are detected when the Euclidean Distance measured to fuse a variable (question) or a respondent with a cluster lies above the threshold. The threshold is equal to the median value of all Euclidean distances plus two standard deviations.
Outliers are also visible on the dendrogram chart of the cluster analysis. In the following image, for instance, variable “What is your favorite ice cream brand? – Open-Ended Response” is an outlier.
