Appendix B. Assessing the quality of evidence and confidence in the risk
Updated 26 January 2023
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Determining the quality of evidence used to estimate the risk
Good quality
The quality of evidence is good if further research is unlikely to change confidence in information.
Examples of types of information or evidence:
- peer reviewed published studies where design and analysis reduce bias, for example systematic reviews, randomised control trials, outbreak reports using analytical epidemiology
- text books regarded as definitive sources
- expert group risk assessments, or specialised expert knowledge, or consensus opinion of experts
- established surveillance systems by recognised authoritative institutions
Satisfactory quality
The quality of evidence is satisfactory if further research is likely to have impact on confidence of information and may change assessment.
Examples of types of information or evidence:
- non peer reviewed published studies or reports
- observational studies, surveillance reports or outbreak reports
- individual (expert) opinion
Unsatisfactory quality
The quality of evidence is unsatisfactory if further research is very likely to have impact on confidence of information and likely to change assessment.
Examples of types of information or evidence:
- individual case reports
- grey literature
- individual (non-expert) opinion
Determining the confidence of the risk assessment output using the quality assessment score
Mostly ‘good quality’
If the quality of evidence is mostly good, confidence of the risk assessment output is good (good quality evidence, multiple reliable sources, verified, expert opinion concurs, experience of previous similar incidents).
Mostly ‘satisfactory quality’
If the quality of evidence is mostly satisfactory, confidence of the risk assessment output is satisfactory (adequate quality evidence – including consistent results published only in grey literature, reliable sources, assumptions made on analogy and agreement between experts or opinion of 2 trusted experts).
Mostly ‘unsatisfactory quality’
If the quality of evidence is mostly unsatisfactory, confidence of the risk assessment output is unsatisfactory (little poor quality evidence, uncertainty or conflicting views among experts, no experience with previous similar incidents).