Drop-Out Analysis shows you data for all responses that are incomplete and gives you a snapshot view of where they “dropped out” – the last question they completed successfully. With the Dropout Analysis, you can dive into your drop-out rates (users not completing the survey).
Drop-Out analysis data is captured based on the last question that was answered for the particular response. If respondents go back in the survey and leave the survey, we cannot determine the last question they answered. In this case, you will see Unknown Questions in your drop-out analysis.