In the literature, there are only a handful of examples where researchers have attempted to validate animal indices. A daunting task. In this presentation, I would like to explore a heuristic alternative to the experimental validation process. If you query statisticians about how one might go about interpreting the data generated by a monitoring program whose index has not been validated, that is, one where you don't explicitly know the relationship between your count and the total population, be sure to turn on your force field, because their phasers are on full. Many papers in this symposium illustrate this fact, in effect, whether the authors so intended or not.
Experience suggests that the index and population density are related, perhaps monotonically.
So, the take-home message here is to never bring up religion, politics, sex, or unvalidated indices at the next cocktail party you attend unless you are very, very sure no statisticians are present. Biologist's though are hardly exemplary when it comes to confronting the rogue index. Statistical analyses of these data and their subsequent interpretations should dwell on the patterns of population change rather than on the magnitudes of calculated trend and variances. Here then lies the problem, the traditional statistician argue for statistically validating indices before developing a new monitoring program or interpreting the data of existing ones. I believe that there is a middle ground.