Surveys play an important role in quantifying user opinion during test and evaluation (T&E). Current best practice is to use surveys that have been tested, or “validated,” to ensure that they produce reliable and accurate results. However, unvalidated (“custom”) surveys are still widely used in T&E, raising questions about how to determine sample sizes for—and interpret data from— T&E events that rely on custom surveys. In this presentation, I characterize the statistical properties of validated and custom survey responses using data from recent T&E events, and then I demonstrate how these properties affect test design, analysis, and interpretation. I show that validated surveys reduce the number of subjects required to estimate statistical parameters or to detect a mean difference between two populations. Additionally, I simulate the survey process to demonstrate how poorly designed custom surveys introduce unintended changes to the data, increasing the risk of drawing false conclusions.
Suggested Citation
Bell, Jonathan L, and Adam M Miller. Statistical Advantages of Validated Surveys over Custom Surveys. IDA Product ID 3001858. Alexandria, VA: Institute for Defense Analyses, 2024.