Carl Schwarz



My research program is in two areas: capture-recapture experiments and statistical consulting in environmental impact studies. It is motivated by real problems encountered by ecologists and health researchers.

My current research projects in ecology are in the estimating of animal abundance, survival, movement and related parameters using mark-recapture methods. Mark-recapture involves the marking of animals (e.g. rings on bird legs; tags on fish; radio collars on large mammals) and then releasing these animals back to their population. Subsequent resightings or recaptures of the marked and unmarked animals allow us to estimate the survival rate, the population size, and the movement rates of the animals.

My health-related research interests are in capture-recapture methods which are known in epidemiological studies as multi-list methods. These are used to estimate the size of populations where incomplete lists are kept of members. For example, how many injecting drug users (IDU) are there in Vancouver? Various social agencies have (incomplete) lists of IDUs. Based on the patterns how which names appears on multiple lists, an estimate of the number of people not appearing on any list can be obtained. As expected, there are serious problems of listing errors (e.g. is J.Smith the same as J.Smithe?) and the ‘probability of capture’ on each of the list is very heterogeneous among sub-populations.

My environmental impact research interests lie in designing and analysing environmental impact studies. This is motivated by my extensive consulting work with Environmental Consulting companies.