Methodological quality | Interpretation | Within a study | Across studies |
---|---|---|---|
Low | Bias may seriously weaken confidence in the results. | The criteria was not met in one or more of the quality domains. | Most information was from low quality studies. |
Moderate | There is a risk of bias that raises some doubt about the results. | The criteria was met, or there was not enough information to judge if the criteria was met for all quality domains. | Most information was from high or moderate quality studies. |
High | Bias, if present, is unlikely to alter the results seriously. | The criteria was met in all the quality domains. | Most information was from high quality studies. |