In the December, 2015, edition of this Science Update we responded to a recent article appearing in The Atlantic.1 Its author, Gabrielle Glaser, claimed that AA and its 12-step programs lack scientific foundation, asserting that “nothing about the 12-step approach draws on modern science …..” We presented the data supporting the opposite case, citing several published scientific reports that she did not mention. In the present installment, we review the basis on which she asserts her claim that the success rate of AA is only 5-8 percent. Relying on a single secondary source2 for this claim, Ms. Glaser writes, “That is just a rough estimate [of AA’s effectiveness], but it’s the most precise one I’ve been able to find.” Because flawed science can cause harm, we offer a critique of the scientific basis she cites for her claim. At the outset, Ms. Glaser’s source presents neither new data nor any of...