Since apparent sharpness is linked to the ability to resolve items, and this is linked to contrast, then the Crawley method will miss any image effects linked to contrast.
There are many ways to measure apparent sharpness, but it must be done at the scale at which you intend to work, and at the contrast you are using. The technical data are hard to interpret, when in actual fact one image may appear sharper than another when the data says the opposite must be true. Nothing beats the eye for telling what is "right", and if your test print vs your test subjects pick one over another, then that is the way to go.
Ok, so, Kriss points out that the grain (or noise in the measurements) also contributes to image sharpness or overall quality and he uses the term "Film Information Capacity" to express all aspects of the quality of a film. In his article, he cites 103 references.