One credit is equivalent to extracting one data point from one respondent, regardless of the number of questions or the amount of prompting required by the agent to obtain the information.
For example:
— “How did you like our delivery? Why?” = 2 data points = 2 credits per interview.
— “How do you like this idea? Likes (probe to get at least 3)? Dislikes (probe to get at least 3)?” = 3 data points = 3 credits per interview.