From: Systematic review of effects on biodiversity from oil palm production
Category | Quality of evidence presented |
---|---|
I. | Randomized controlled trials of adequate spatial and temporal scale for the study species. |
II. | Controlled trials without randomization with adequate spatial and temporal scale for the study species. |
III. | Comparisons of differences between sites with and without controls with adequate spatial and temporal scale for the study species. |
IV. | Evidence obtained from multiple time series or from dramatic results in uncontrolled experiments. |
V. | Opinions of respected authorities based on qualitative field evidence, descriptive studies or reports of expert committees. |
VI. | Evidence inadequate owing to problems of methodology e.g. sample size, spatial or temporal scale. |