Real and quasi-experiments in capture-recapture studies

The three key elements of experimental design are randomization, replication, and variance identification and control. Capture-recapture experiments usually pay sufficient attention to the first two elements, but often do not pay sufficient attention to sources of variation. These include blocking factors and different sizes of experimental units. By casting capture-recapture studies in an experimental design framework, the various roles of these sources of variation become clear and the sources that are pooled when these experiments are analysed using existing software is also clear. This formulation also shows that care must be taken with pseudo-replication and different sized experimental units.