An article by Snopes in 2013 said the experiment was flawed because the methods used were suspect, the sample size was much too small, and the capability to measure weight changes too imprecise, concluding: "credence should not be given to the idea his experiments proved something, let alone that they measured the weight of the soul as 21 grams."[4] The fact that MacDougall likely poisoned and killed fifteen healthy dogs in an attempt to support his research has also been a source of criticism.[2][4]