G.R. Carmody¹, B. Leclair², C.J. Frégeau², J.C. Elliot², K.L. Bowen² and R.M. Fourney^2
1 Department of Biology, Carleton University, Ottawa, Ontario, Canada
² Biology Research and Development, RCMP Central Forensic Lab, Ottawa, Ontario

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Population studies of Canadian Caucasian and three Canadian Aboriginal databases, together with precision studies at 10 STR loci, have shown the appropriateness of using a floating-bin approach to calculate frequency estimates of DNA genotypes. Fixed-bin calculations are conceptually easier to understand and practically simpler to do manually from tables. Floating-bin calculations however, are cumbersome without a computer. A program, called STRquest, was developed and implemented on both Windows and Mac operating systems. The program does the floating-bin calculations on all four population databases using the recommendations of the 1996 National Research Council Report. The program can be relatively easily modified to use other databases. It has been developed in collaboration with forensic analysts to provide a convenient, user-friendly environment for preparing statistical summaries of the data for courtroom interpretation. Comparisons are show of calculations using both fixed- and floating-bin approaches on casework samples. The floating-bin method gives statistically precise estimates based on the match-window criterion without having to make ad hoc rebinning decisions.