Perhaps the most notorious example is the excess of positive findings in “imaging genetics” studies that has been revealed in several recent analyses of publications in this field (Flint and Munafo, 2012; Ioannidis, 2011; Ioannidis and Trikalinos, 2007). These analyses estimated the expected proportion of positive findings of association given statistical power and the reported effect size, and compared it with the observed rate of positive reports. The results indicated strong biases towards reporting positive findings, probably due to selective outcome reporting and selective analyses reporting.
