The article states: "Before going further, let’s dispel the myth that these research results are due to a handful of poorly constructed studies. In fact, it’s

The article states: "Before going further, let’s dispel the myth that these research results are due to a handful of poorly constructed studies. In fact, it’s the opposite. Cooper compiled 120 studies in 1989 and another 60 studies in 2006." However, the 2006 meta-analysis explicitly says that all 60 studies had design flaws. To quote the conclusion: "We hope that this report has demonstrated the value of research synthesis for testing the plausibility of causal relationships even when less-than-optimal research designs and analyses are available in the literature."