This post was a response buried deep in a thread on the Equinox Forum, but got long enough on a subject I think about a lot, that it deserved its own thread. Here you go.
I find the whole George Payne way of conceptualizing things to be rather out of date myself. That was back in the day when only one thing mattered - detecting coins. Silver coins in particular. So he was looking at frequency, and most importantly, coin size targets.
If you do that, fix target size, you get the false i