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Tracking Again...

I'm still thinking about this one. I had an additional thought about this. It is possible to predict which cases are likely to be difficult to locate. Couper and Oftedal have an interesting chapter in the book Methodology of Longitudinal Surveys on the topic. I also recall that the NSFG Cycle 5 documentation had a model for predicting probability of locating someone.

Given that information, it should be easy to stratify samples for differential effort. For instance, it might be better to use expensive effort early on some cases that are expected to be difficult. If this saves on the early inexpensive steps. The money saved might be trivial. But the time could be important. If you find them more quickly, perhaps you can more easily interview them.

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