8 - Evaluating evidence

Summary

Introduction

The preceding chapters focused upon the logic of proof and methods for analyzing evidence in a variety of contexts – for example, analyzing the evidence in an ongoing investigation or in a decided case or in preparing for trial. It should be clear, however, that developing the strongest theory of a case and determining how the evidence can best be marshaled to support a probandum necessarily requires that the analyst make evaluative judgments. So far, we have not directly addressed the problems of or techniques for evaluating the probative value of evidence or the strength or cogency of arguments about particular aspects of the evidence or about the evidence in a case-as-a-whole. This chapter and the next focus upon those problems and techniques.

A lawyer must confront the problems at every stage of a case. For instance, in a civil case, from the initial interview onward, the lawyer must assess the weight and force of the evidence that is available and that is likely to become available. Should the case be taken? Filed? Pursued? Is the case ready for trial or is further investigation or discovery justified or required? Given the available evidence and the operative law, should the case be settled and, if so, on what basis? At trial, the questions concern both the lawyers and the decision-makers. Does the particular evidence proffered have such probative value that it should be admitted notwithstanding any improper prejudicial effects that it may have?