Example: The Importance of Evaluating All Lines of Evidence

All lines of evidence should be described and interpreted. It may be tempting to eliminate data or study results that seem of poor quality, but doing this could lose valuable information.

As an example, let's return to the carbofuran/bird mortality assessment. (This assessment appeared earlier in the modules in the variations in environmental conditions between regions activity, as an example use of field surveys for risk estimation, and in demonstration of the quotient method.)

As described earlier, field studies and the quotient method were used to show that carbofuran causes bird mortality. While these approaches are relevant to the assessment endpoint, both were flawed to some extent. The quotients were limited in their ability to express incremental risks (e.g., how much greater risk is expressed by a quotient of "2" versus a quotient of "4"), and the field studies had some design flaws. Nevertheless, because of the strong evidence of causal relationships from the field studies and consistency with the laboratory-derived quotient, the risk assessors could conclude with confidence that the risk was high.