noted above, are well represented in the MTFS), our largest effect accounted for .33% of the variance. We would need 20,000 individuals to have sufficient power to detect an effect of this magnitude. Even with such a large sample, that would likely be the only effect we would have the power to detect because most effects can be expected to be considerably smaller in magnitude. If samples of tens of thousands are required to unravel endophenotype genetics and considering, as Baker (2014, this issue) points out, that their relevance to the genetics of psychopathology would still need to be determined, they are not likely to serve well their intended purpose of facilitating psychiatric disorder gene finding.
