primary data, utilizing variables that are harmonized across the datasets and with analyses that were determined a priori. These analyses will be implemented in a set of primary analyses, arising from the original report of a GxE interaction involving 5-HTTLPR variation, and supplemented by secondary analyses intended to aid in the interpretation of the main findings and to address numerous issues related to possible heterogeneity between the contributing studies. The risk of data mining and of type 1 errors in large, multidimensional datasets such as ours is great, and there is a clear need for consensus on best practice before analyses are conducted. It is our hope that by publishing this protocol in advance of all analyses being conducted, we will minimize potential biases.
