There is a very specific claim here that doesn't really need to be shown with quantitative analysis if he's truly a knot expert. In the Michigan example, he no

There is a very specific claim here that doesn't really need to be shown with quantitative analysis if he's truly a knot expert. In the Michigan example, he noted that the knot used was one that only a butcher would use and that the other guy was a mechanic. Presumably he knows a lot about knots, and he would know what kinds of knots were common across different occupations because knots have specific uses, and he probably knows the few knots that a mechanic uses and a few that a butcher uses and pointed it out. There's no need to conclusively prove that a certain person can be shown to have tied a knot to buy his claims. Only that in cases where one accused is in an occupation that has a distinguishably common/uncommon knot ratio compared to another occupation with a different distinguishably common/uncommon knot ratio, that the information about which knot was used used can, well, distinguish between the occupations. Plus, he basically said "the butcher did it" and the guy immediately confessed, its not like it help up in court.