How large is large? : preliminary and relative guidelines for interpreting partial correlations in economics
Hristos Doucouliagos
An essential part of empirical economics research is the identification of the size of an empirical effect. Partial correlations offer a convenient statistically based measure of the strength of an economic relationship. A key question arises in their interpretation: When is a partial correlation large? This paper draws upon the observed distribution of 22,000 partial correlations from a diverse group of economics fields. The median absolute partial correlation from these fields is 0.173, which under Cohens (1988) conventional guidelines for zero order correlations is a small to moderate effect. The paper develops new guidelines for key qualitative categories (small, medium and large). According to the new guidelines, partial correlations that are larger than ± 0.33 can be deemed to be large. This is considerably different to Cohens guideline of ±0.50 for zero order correlations. Researchers and metaanalysts should exercise caution when applying Cohens guidelines to describe the importance of partial correlations in economics. partial correlations; guidelines; empirical economics; meta-analysis