Washington Post/ Tamar Haspel: “The Agriculture Department recently released the latest measurements of pesticide residues in our food, in the form of the 2016 Pesticide Data Program results, so it seems timely to talk pesticides and organics. And bias. I’ve been following these issues for a long time, and I’ve seen a lot of evidence that organic foods have lower levels of pesticide residues than conventional foods, so I was surprised to read a two-part analysis on Forbes.com by Steve Savage, a conventional-side plant scientist I know and respect, showing that the number of residues, and the amount of pesticide in those residues, were virtually the same for organic and conventional foods. What could be happening in our food supply for the difference in pesticide levels to narrow so markedly? That would make an interesting column, I thought. So I started asking people, but nobody had a good explanation. There’s no evidence for widespread fraud (although there’s evidence for some), and the only other explanation was drift. Because organics are often grown in the proximity of their conventional brethren, drift happens. But that’s an awful lot of drift. And then I talked with Sonya Lunder, senior analyst at the Environmental Working Group. She’s also a data geek, a woman after my own heart, and she had actually tried to replicate Savage’s results. She couldn’t. So I figured I’d better try to do it myself. And I couldn’t, either.

The reason we couldn’t was that Savage’s data were spectacularly wrong. He reported that conventional foods had an average of 3.1 different pesticides, and organic had 2.6. The real numbers, which I downloaded the entire residue database to get, are 3.2 for conventional (okay, that’s close), and 0.8 for organic (definitely not close). I called the USDA to make sure I hadn’t screwed something up, and it confirmed my numbers. This was an honest mistake, and when I pointed it out, Savage immediately checked for himself, confirmed the error and set about retracting the articles. He told me he felt terrible for getting it wrong…