ABSTRACT
This chapter begins the discussion of the processes and activities involved with conducting a causal assessment. It suggests strategies for formulating problems in causal assessments. The assessment process consists of three major parts: formulating the problem, deriving evidence, and forming conclusions. The chapter begins by describing how the broad and sometimes vague concerns that initiate a causal assessment can be sharpened to define the specifics of the case. Causal assessments of specific cases are initiated because undesirable biological conditions have been observed. The chapter discusses defining the undesirable effects of concern and the spatial and temporal extents of the assessment. These two topics are often explored simultaneously when an undesirable effect is recognized and a causal assessment is begun. If a watershed-scale cause is operating, it is relatively easy to combine the results of multiple reach-scale or tributary-scale causal analyses or to extrapolate the local-scale results to the rest of the watershed.
