What is the incidence rate?

Incidence rate is a common metric used in surveying. Simply put, it measures the fraction of a sample that met a certain condition or completed the survey.

For example, we might survey 300 people from a general population (without any screening criteria) and find that the incidence rate of dog ownership is 20%.

When using a predefined panel from Conjoint.ly we, generally cannot approach incidence rate in the same way as above. This is because predefined panels are sourced from profiled respondent pools, which means that a panel that requires respondents to be dog owners will only invite respondents who are already known or likely dog owners. Therefore, when reviewing the screening data, if we find that 75% of respondents who began the survey were in fact dog owners, we cannot apply this incidence rate to the general population.