Sensitivity Analysis and Nonresponse Bias

For a while now, when I talk about the risk of nonresponse bias, I suggest that researchers look at the problem from as many different angles as possible, employing varied assumptions. I've also pointed to work by Andridge and Little that uses proxy pattern-mixture models and a range of assumptions to do sensitivity analysis. In practice, these approaches have been rare.

A couple of years ago, I saw a presentation at JSM that discussed a method for doing sensitivity analyses for binary outcomes in clinical trials with two treatments. The method they proposed was graphical and seemed like it would be simple to implement. An article on the topic has now come out. I like the idea and think it might have applications in surveys. All we need are binary outcomes where we are comparing two groups. It seems that there are plenty of those situations.

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My dissertation was entitled "Adaptive Survey Design to Reduce Nonresponse Bias." I had been working for several years on "responsive designs" before that. As I was preparing my dissertation, I really saw "adaptive" design as a subset of responsive design.

Since then, I've seen both terms used in different places. As both terms are relatively new, there is likely to be confusion about the meanings. I thought I might offer my understanding of the terms, for what it's worth.

The term "responsive design" was developed by Groves and Heeringa (2006). They coined the term, so I think their definition is the one that should be used. They defined "responsive design" in the following way:

1. Preidentify a set of design features that affect cost and error tradeoffs.
2. Identify indicators for these costs and errors. Monitor these during data collection.
3. Alter the design features based on pre-identified decision rules based on the indi…

Future of Responsive and Adaptive Design

A special issue of the Journal of Official Statistics on responsive and adaptive design recently appeared. I was an associate editor for the issue and helped draft an editorial that raised issues for future research in this area. The last chapter of our book on Adaptive Survey Design also defines a set of questions that may be of issue.

I think one of the more important areas of research is to identify targeted design strategies. This differs from current procedures that often sequence the same protocol across all cases. For example, everyone gets web, then those who haven't responded to  web get mail. The targeted approach, on the other hand, would find a subgroup amenable to web and another amenable to mail.

This is a difficult task as most design features have been explored with respect to the entire population, but we know less about subgroups. Further, we often have very little information with which to define these groups. We may not even have basic household or person chara…

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