The 4PL

(Click on "Preview" below the photo at the left to see inside.) This book explains the mathematical form of the four-parameter logistic model that is the basis of many current bioassays. You'll acquire an understanding of how relative potency is estimated by comparing two 4PL models. You’ll learn what probits are, why so called “probit analysis” was once necessary to estimate relative potency, why probit analysis (and "logit analysis") became known as “parallel line analysis.” You’ll also see why some questionable extensions of parallel line analysis are easily manipulated by the bioassayist and should raise the eyebrows of regulatory agencies. You’ll see why analytic dilution assays are so robust and forgiving of certain mistakes and blunders made by the bioassayist. You’ll be introduced to historical figures like Trevan, Bliss, Gaddum, Wood, Finney, Jerne, Hill, and others, and you'll appreciate the hard work and deep thinking they did to bring us to where we are today.