The hypothetical measure of “relative research benefit”. Compared to the recruitment of singletons, what would be the benefit of using the same efforts for recruiting families? We would recruit fewer families, but theses families might give us more genetic information. As you can see from the chart, family recruitment of dominant families only makes sense if the families are sufficiently large. In smaller dominant families, there will be too much genomic noise to identify the causative gene. Accordingly, recruiting small families may lead us into the “valley of despair”. The relative research benefit increases only if the families become sufficiently large.