Multipopulation survey designs: five types with seven shared aspects.

"Five types of multipopulation surveys are defined and described: periodic surveys; multidomain designs; multinational survey designs; cumulated and combined samples; and controlled observations or quasi- experimental designs. I emphasize the deliberate designs of these surveys, not the mere post hoc or ad hoc utilization of survey results. Most importantly, I emphasize a sharp distinction between seven listed aspects. Similarity and standardization of the survey aspects (definitions, methods, measurements) are essential to avoid biases in comparisons, though admittedly difficult. In contrast, flexibility in sampling designs and sizes, to reduce variances, is permissible, also desirable to reduce variances and costs." (SUMMARY IN FRE) excerpt