The length of interview (LOI) is how long you estimate it will take a respondent to fully complete your survey. The maximum LOI allowed on TapResearch is 30 minutes.
Incidence rate (IR) is the percentage of respondents 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.
We suggest to calculate incidence after you've finished the targeting for your project. Proper targeting will provide a higher incidence, lower cost, and help your survey run more smoothly.
Example: If you are looking for respondents in New York City, the incidence will be low if you target the entire US. If you target the New York City DMA, your survey will only be sent to respondents in that area and IR will be higher.
Days in field is how many days you anticipate the survey will be open. This field is only to help estimate feasibility and will not change, limit, or effect fielding in any way.