[WS:] Try Stephen Jay Gould "The Mismeasure of Man" he is pretty good at explaining the fraudulent use of statistics behind IQ testing and its derivatives - "scholastic aptitude" and similar bullshit. And he knows the science.
In a nutshell, Gould argues that statistical techniques, no matter how sophisticated they look, can only go as far as the assumptions underlying the calculations, and those assumptions are often questionable or outright fraudulent. He quotes the example of factor analysis which is a regression-based technique of estimating "latent" factors or commonalities among multiple empirical indicators. Computationally, the problem is expressed as a system of multiple equations of the form y=a+bx+e where x is empirically observed and other parameters are estimated i.e. y is the "latent" factor a is the intercept, b is regression coefficient and e is the error term. In order to be mathematically solvable, certain assumptions must be made about the parameters to be estimated i.e. y's and e's which in practice means specifying how many factors you want there to be. For example, if you have 30 empirical indicators, you tell the machine to find k number of latent factors where k ranges from 1 to 30, and the machine will find them no matter what because it was programmed to do so.
The fraud part comes in the interpretation of the machine output. The IQ fraudsters tell the machine to find a single factor (general intelligence) because they a priori believe that human intelligence is uni-dimensional and as such can be hierarchically arranged. That it its main political advantage - it scan be used as pseudo-scientifically justified measure of "moral worth" or "merits." The IQ fraudsters use the results as a proof that such a single factor exists as supposedly "proved" by statistics. In reality, however, statistics do not prove that a single factor exists - they only show a solution for one factor because only was factor was assumed, but they can show a solution for any number of factors as long as the number of factors is smaller than the number of variables in the equation.
In substantive terms it means that human IQ or "aptitude" or "merits" or any kindred bullshit measured by the testing-industrial complex can be assumed to be either one dimensional or multi-dimensional and the number of dimensions depends on what the researchers want it to be. A single dimension or may be two dimensions (verbal vs. quantitative) are preferred, because they can be hierarchically arranged and thus serve as "scientific" indicator of an individual moral worth. Multiple dimensions (e.g. verbal, quantitative, emotional, social, psychomotor, visual, aural, etc.) do not yield themselves to hierarchical arrangements. If one person is high on quantitative but low on verbal and emotional, and another high on emotional and social but low on quantitative - who is "better" or more "meritorious"?
Another noteworthy point that Gould makes is that the real danger of this "measurement of man" is posed not by outright fraudsters who "cook their numbers" but by reputable scientists who use correct statistical procedures but interpret them in way that is supportive of their hidden agenda. Cooking the numbers can be easily exposed, but biased interpretation of mathematically correct results generally passes for bone fide science.
It follows that the way to expose fraud behind measures of human worth is not to be distracted by the statistical technique, which in most cases passes the smell test, but go for the jugular of the people who produced them, and expose their implicit assumptions and agendas, options they did not consider, etc.
Wojtek