Assessing and Categorizing Health-Related Expert Opinion(s) and Scientific Evidence

Purpose

The purpose of this policy is to provide general guiding principles for experts asked by Veterans Affairs Canada (VAC) to provide an opinion assessing and categorizing health-related expert opinion(s) and scientific evidence in relation to causality, for the purposes of disability benefit entitlement. 

Policy

Definitions

1. For the purposes of this policy, the following terms are defined as:
   1. Association: A factor and a health outcome are said to be associated when the two appear to occur together. Associations can be explained by chance, bias or confounding, or causality.
   2. At least as likely as not that causality exists: On balance, health-related expert opinion(s) and scientific evidence is equally for and against causality and it cannot be determined which is stronger.
   3. Causality: The relating of causes to the effects they produce; a relationship between a factor and a health condition where exposure to the factor earlier in life results in the health condition later in life, as in a causal relationship.
   4. Evidence: Any form of proof that is offered to substantiate a claim and/or to establish the existence or non-existence of any fact in dispute.
   5. Health-Related Expert Opinion(s) and Scientific Evidence: Evidence comprised of opinions of experts and results of scientific research. Examples include, but are not limited to, results of scientific studies, reviews of scientific studies, opinions of other medical/scientific experts, and experts’ clinical experience.
   6. Insufficient to form an opinion about causality: Health-related expert opinion(s) and scientific evidence is not sufficient to conclude that causality exists without speculating.
   7. More probable than not that causality exists: Health-related expert opinion(s) and scientific evidence supports causality with a degree of certainty of more probable than not or greater.
   8. More probable than not that causality does not exist: Health-related expert opinion(s) and scientific evidence supports the lack of causality with a degree of certainty of more probable than not or greater.

Guiding Principles

2. The expert should follow these steps when weighing and categorizing other expert opinion(s) and scientific evidence:
   1. Acquire - Gather the evidence. VAC may acquire evidence from a number of sources, not solely the evidence being presented by applicant.
   2. Assess - Determine the strength of health-related expert opinion(s) and scientific evidence, using standard principles of epidemiology and critical review.
   3. Adapt – Synthesize the findings and communicate opinion and certainty of opinion as follows:
      1. Category 1 – More probable than not that causality exists
      2. Category 2 - At least as likely as not that causality exists
      3. Category 3 - Insufficient to form an opinion about causality
      4. Category 4 – More probable than not that causality does not exist
3. The VAC decision-maker will consider and weigh the opinion as part of the entitlement decision making process. The expert’s opinion is not binding on the VAC decision-maker. The decision-maker will assess the opinion along with all the evidence, make findings of fact and apply VAC’s legislation when making a decision. For VAC purposes, causality (a finding of fact) is more likely to be inferred when the expert's opinion is category 1 or 2 (at least as likely as not or stronger).

References

Pension Act, subsection 5(3)

Veterans Well-being Act, section 43

Benefit of Doubt