Table 2 Critical Appraisal for assessing the quality of each individual source
| Â | Very high | High | Moderate | Low | Very low |
|---|---|---|---|---|---|
5 | 4 | 3 | 2 | 1 | |
Quality of literature | An extensive body of high-quality evidence in review format | A developing body of high-quality evidence in review format | Studies of the highest quality (randomised control trial equivalent) | Studies using quasi-experimental methods | High quality observational studies only |
Relevance of context | As level 4, but with excellent contextual and implementation insight drawn from high-quality studies and on-farm practice | Includes evidence generated in farming and growing businesses with farmers and growers testing the practice | Evidence generated in farming and growing businesses with the practice applied by professional researchers | Evidence generated in research centre farming and growing facilities | Evidence generated through laboratory research |
Relevance of region (here in scope: arable systems in Europe) | European focused study and relevant crops | Global study which includes direct reference to relevant regions (i.e., Europe) | Global study which may be relevant to target regions, but this is not specific | Potentially irrelevant region for this context, e.g., China but includes useful findings | Irrelevant geographical context—i.e., tropical areas. Not included within the matrix |
Overall | We can draw very strong conclusions about impact and be highly confident that the practice does/does not have an impact The body of evidence is very diverse and highly credible, with the findings convincing and stable | We can draw strong conclusions about impact and be confident that the practice does/does not have an impact The body of evidence is diverse and credible, with the findings convincing and stable | We can draw some conclusions about impact and have moderate confidence that the practice does/does not have an impact The design of the research allows contextual factors to be controlled for | We believe that the practice may/may not have an impact. The body of evidence displays significant shortcomings There are reasons to think that contextual differences may substantially affect practice outcomes | The body of evidence displays very significant shortcomings There are multiple reasons to think that contextual differences may unpredictably and substantially affect practice outcomes |