How should forensic scientists present source conclusions?

The question I will address is how forensic scientists should communicate source conclusions in reports and testimony. The answer, I will argue, depends on two issues: (1) what conclusions can be justified logically and empirically; and (2) what conclusions (among those that can be justified logically and empirically) are most likely to be understood and used appropriately. I will first review various possible ways that forensic scientists might report source conclusions, pointing out logical and empirical difficulties with some reporting methods. Then I will discuss what is currently known about lay understanding of such reports.