The first one is for setting a limit number of messages within a time interval.
This means that a participant can receive multiple or up to the limit number of messages within a short time. Participant will not receive message if the limit is hit until the stated time interval has passed.
Scenario: I have 100 surveys for participants. Contact frequency is set-up as 100 messages in 30 days.
Behavior: This will allow up to 100 survey invitations to the same participant on the same day within 30 days period.
Result: I can send all 100 surveys invitation and complete it within a short timeframe of minutes or hours.
The second one is for setting a requirement for participants to only receive message after duration have passed.
Scenario: I have 100 surveys for participants. Contact frequency is set-up as a day being required based on last invitation.
Behavior: This restricts survey invitations and participant will only receive one survey invitation at maximum each day.
Result: If I were to send out all 100 surveys invitation, I will need a minimum of 100 days to complete.
