Natural fallout and quotas
Natural fallout refers to the consequences of running a survey with no quotas in place to manage who is permitted to enter the survey. As a result, we allow the audience, regardless of their demographic or behavioral characteristics, to “naturally fall out”, meaning the required survey completes will be filled by whoever reaches the survey before the limit is reached.
Natural fallout enables a more representative sample for variables where the composition of the universe is unknown, but it will have some level of variability when it comes to the audience composition. Natural fallout studies also tend to be much easier for us to fulfill, as any respondent can enter the survey.
The alternative to natural fallout would be to use quotas - like age, gender, or region - to balance who enters the survey based on set criteria. Quotas establish specific targets for the number (or proportion) of people in the sample with a particular characteristic (e.g. n=75 women and n=75 men in a sample of n=150). This means the number of respondents for each characteristic is managed throughout the survey, with respondents being rejected when the quota for a particular characteristic is full. Quotas enable full control over the number of respondents with specific characteristics but tend to be slower to field as only specific respondents can enter the survey.
How does Zappi use quotas?
As a standard practice, Zappi uses quotas on gender and age, with natural fall out being used typically in demographics like region, as well as non-demographic variables, such as category consumption. Your sample will likely use both quotas and natural fallout at different parts of the screener. Our sampling experts determine the optimal sampling strategy for each audience built in the Zappi platform.