* includes EMA’s

Maintaining Telephone Response Rates

In order to maximize representation and reduce bias, NADbank employs a rigorous sampling platform.  The following is the callback produces applied to the sample: 

• Busy: A callback was made every 30 minutes, to a maximum of 3 times in one evening.
• No Reply Or Answering Machine: A callback was made every 60 minutes, to a maximum of 2 times in one evening.
• Household Contact Indicates It Is Not Convenient Today: The next call was made on the designated day of week the following week. However, the time was advanced forward or backward by 90 minutes.
• Refusals: Household and respondent refusals were suspended for 2 weeks. They were recalled as follows:
  1. 1st refusal: Recalled two weeks later on the design day of week.
  2. 2nd refusal: Recalled two weeks later on the design day of week.
  3. 3rd refusal: The number was suspended.
• Deactivation: A number was deactived only if it met any one of several conditions (please refer to the Technical Report)

In addition, all remaining active telephone numbers in the sample, including first and second refusals, and appointments are brought forward and dialed in week 13 of each stream in all markets.

Refer to the NADbank Technical Report for more information on NADbank's sampling platform.