The survey length is how long you estimate the survey to take a respondent to complete. It takes roughly 1 minute to complete 2.5 questions.
The time in field is how long you anticipate the survey being open for.
Incidence rate is the percentage of people that will qualify for the survey. In the screenshot below we are assuming 70% of people who enter the survey will be able to complete it.
Within the TapResearch tool, calculate your incidence after you've targeting. Proper targeting will provide a higher incidence, lower cost, and help your survey run more smoothly.
For example- If you are looking for respondents in New York City, incidence will be very low if you target the US. However, if you target the New York DMA that will exclude the rest of the US and your incidence will be high.
(For more information on incidence, see here)