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United States Environmental Protection Agency
Causal Analysis/Diagnosis Decision Information System (CADDIS)
Begin Hierarchical Links EPA Home > CADDIS > Step-by-Step Guide > Step 2: List Candidate Causes End Hierarchical Links
Step-by-Step Guide
  Step 1: Define the   Impairment
  Step 2: List Candidate   Causes
  Step 3: Eliminate
  Step 4: Diagnose
  Step 5: Compare   Strength of Evidence
  Step 6: Identify   Probable Cause
 
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Step 2: List Candidate Causes  This image is a drawing of a caddisfly larva in its case. Caddisflies are aquatic insects that are used by biologists to monitor the environmental quality of streams.
Download Worksheets for Step 3
3.3. Results and Next Steps
 

At the conclusion of Step 3, the evidence from the case has been summarized and you should have three products:

  • A summarization of the supporting data, analyses, and scoring rationale for each type of evidence that was evaluated (example analysis worksheet for spatial co-occurrence),
  • A table containing all of the scores you assigned (example scoring table), and
  • A list of the causes that you either eliminated or diagnosed. This list is formed by first scrutinizing the negative results, which are more likely to be decisive and may have been strong enough to refute a candidate cause. You should also carefully review evidence of symptoms that were strong enough to score a "D" (for diagnosed) or "R" (for refuted), to make certain those symptoms are sufficiently characteristic of a candidate cause to support the conclusion.

These three sets of results are still interim products. The results for the candidate causes that are refuted or diagnosed are set aside until overall conclusions are made in Step 5. For the candidate causes that remain, additional evidence using data and information from outside the case is sought in Step 4.

Next: 3.4. Spatial/Temporal Co-occurrence     Continue to Step 4
Download Worksheets for Step 3
 

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