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Showing posts from December, 2015

Mode Sequence

A few years ago, I did an experiment with two sequences of modes for a screening survey. The modes were mail and face-to-face. We found that the sequence didn't matter much for the response rate to the screener, but that the arm that started with face-to-face and then used mail had a better response rate to the main interview given to those who were found to be eligible in the screening interview.

There are other experiments that use different sequences of modes. Some of these find that the sequence doesn't matter. For example, Dillman and colleagues looked at mail-telephone and telephone-mail and these had about the same response rate. On the other hand, Millar and Dillman found that for mail-web mixed-mode surveys the sequence does seem to matter, although certainly the number and kind of contact attempts are also important.

It does seem that there are times when the early attempts might interfere with the effectiveness of later attempts. That is, we "harden the refusal…

Myopic Calling Strategies

I'm interested in sequential decision-making problems.In these problems, there is a tension between exploration and exploitation. Exploitation is when you take actions with more certainty about the rewards. The goal of exploitation is to get maximum reward to the next action given what is currently known. Exploration is when you take actions with less certainty. The goal is to discover what the rewards are for actions about which little is known.

A strategy that always exploits is called myopic since it always tries to maximize the reward of the current action without any view to long-term gains.

Calling algorithms certainly face this tension. For example, evenings might be the best time on average to contact households. If I know nothing else, then that would be my guess about when to place the next call. But it would be foolish to stay with that option if it continues to fail. If I have failures in that call window, I might explore another call window to try and see if the rewar…