In my last post, I talked about the costs of collecting interviewer observations. These observations have to reduce total survey error (likely nonresponse error) in order to justify this cost.

The original definition of paradata was that it was a by-product of the data collection process. Computers stored information on keystrokes at basically no extra cost. Call records were necessary to manage the data collection process, but they were also found to be useful for developing nonresponse adjustments and other purposes.

At some point, interviewer observations became paradata. I think many of these observations started out as information that interviewers recorded for their own purposes. For example, listers would record if there were any barriers to entering the segment (e.g. gated communities or locked buildings) so that interviewers would know about that before traveling to the segment. These could be thought of as no cost.

But we have added a lot of observations that the interviewers don't need for their purposes. These are strictly designed for nonresponse monitoring and adjustment purposes. These do require time and effort for interviewers to record them.

It might be good to think about more ways to passively collect useful data. Smartphones, for instance, can collect many new kinds of data. I accidentally came across this article on the use of smartphones in research and this one as a recent example. Perhaps these sorts of passive data collection can be harnessed to provide useful data for monitoring and adjusting for nonresponse.

### "Responsive Design" and "Adaptive Design"

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…

### An Experimental Adaptive Contact Strategy

I'm running an experiment on contact methods in a telephone survey. I'm going to present the results of the experiment at the FCSM conference in November. Here's the basic idea.

Multi-level models are fit daily with the household being a grouping factor. The models provide household-specific estimates of the probability of contact for each of four call windows. The predictor variables in this model are the geographic context variables available for an RDD sample.

Let $\mathbf{X_{ij}}$ denote a $k_j \times 1$ vector of demographic variables for the $i^{th}$ person and $j^{th}$ call. The data records are calls. There may be zero, one, or multiple calls to household in each window. The outcome variable is an indicator for whether contact was achieved on the call. This contact indicator is denoted $R_{ijl}$ for the $i^{th}$ person on the $j^{th}$ call to the $l^{th}$ window. Then for each of the four call windows denoted $l$, a separate model is fit where each household is assum…