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Table 1 Description of the categories of quality of evidence, organized after adaptation and modification of the guidelines and the hierarchy of evidence quality by Pullin & Knight [ [8]], Pullin & Knight [ [9]] and Pullin & Stewart [ [10]]

From: What is the impact of kelp forest density and/or area on fisheries?

Category Quality of evidence
I Evidence obtained from quantitative, random and/or replicated studies. This include quantitative data obtained by estimates of abundance (biomass and/or percentage cover for seaweeds and abundance for fishes), along randomly chosen and appropriately replicated transects, sampling points and/or quadrats.
II Evidence obtained from quantitative not properly designed studies (failing randomization, replication and control when applicable).
III Evidence obtained from qualitative field evidence, descriptive studies or reports of expert committees.
IV Evidence inadequate owing to problems of methodology e.g. sample size, length or comprehensiveness of monitoring or conflicts of scientific evidence.