A special issue of Perspectives on Psychological Science, published by the American Psychological Society, invited opinions from a variety of psychologists, including us (Diener, 2009). Our advice was to keep it simple (Peterson, 2009). We offered this advice not because simplicity is a virtue, although it is (Comte-Sponville, 2001). Rather, the evidence of history is clear that the research studies with the greatest impact in psychology are breathtakingly simple in terms of the questions posed, the methods and designs used, the statistics brought to bear on the data, and the take-home messages.