Introduction

Factors Determining the Rating

Explicit heuristics will be applied to support two judgments about the findings of each qualifying study about a given outcome (or outcome domain) for a given intervention:

1. The direction, magnitude, and statistical significance of the empirical effect estimate. This will be characterized as a statistically significant positive, substantively important positive, indeterminate, or statistically significant negative effect.
    
2. The quality of the research design generating the effect estimate. This will be characterized as a strong or weak design. (See the WWC Study Review Standards for further details.)

The rating scheme based on these two factors is presented below. After that are the detailed descriptions and heuristics for making the judgments on these factors for each study and outcome.