This is an excellent piece, but the writer is also working on the assumption that an item marked "ships from and sold by Amazon" is a reliable control group ver

This is an excellent piece, but the writer is also working on the assumption that an item marked "ships from and sold by Amazon" is a reliable control group versus a third-party seller. As many know, Amazon's practice of commingling inventory in its Fulfilled by Amazon program can just as easily result in a fake being sold by Amazon as from a third-party seller. The author got lucky and didn't get any fakes in the control group (though one might not rule out the possibility of a more sophisticated counterfeit!), but it will continue to be a risk so long as Amazon continues commingling in FBA.