Publication bias is an effect of questionable research practices that have been corrupted the published record. One example of phenomena when scientists tend to publish studies supporting their hypothesis and putting aside those that do not are called the file-drawer problem (Rosenthal, 1979).
We are currently working on the meta-analyze (link). The effect size of our main interest is calculated for the interaction between two or three conditions. Unfortunately, many older papers do not report the effect sizes.