An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

CADDIS Volume 1

Causal Characteristics and Types of Evidence

The types of evidence and the characteristic of causation that they can represent are presented in Tables 5-3 and 5-4. Some types of evidence can support more than one characteristic, depending on how the study is designed.

The first set (Table 5-3) is based solely on evidence from the impaired site and associated comparison sites (i.e., sites that are part of the case). The second set (Table 5-4) uses knowledge gained from other studies to show that conditions at the impaired site could reasonably be expected to result in specific biological effects. Therefore, evidence for temporality and co-occurrence come only from the site. Evidence for coherence and sufficiency are more likely to come from other field and laboratory studies. Used together they make a stronger case that can help us identify probable causes of impairment in our environment.

Table 5-3. Characteristics of Causal Relationships Supported by Different Types of Evidence that Use Data from the Case
Type of Evidence Characteristic of Causal Relationships
Spatial/Temporal Co-occurrence Co-occurrence
Evidence of Exposure or Biological Mechanism Interaction
Alteration
Causal Pathway Antecedence
Stressor-Response Relationships from the Field Co-occurrence
Manipulation of Exposure Co-occurrence
Temporality
Laboratory Tests of Site Media Sufficiency
Temporal Sequence Temporality
Verified Prediction Alteration
Symptoms Alteration

Top of Page


Table 5-4. Characteristics of Causal Relationships Supported by Types of Evidence that Use Data from Elsewhere

Type of Evidence Characteristic of Causal Relationships
Stressor-Response Relationships from Other Field Studies Sufficiency
Stressor-Response Relationships from Laboratory Studies Sufficiency
Stressor-Response Relationships from Ecological Simulation Models Sufficiency
Mechanistically Plausible Cause Alteration
Manipulation of Exposure at Other Sites Sufficiency
Analogous Stressors Alteration

Top of Page