“To me, to be frank a score of 162 or whatever on a test means nothing, and I hardly care if the test is Cattels , WISC or stanford-binet. When a lay person sees a score of 100 or 160 he assumes that a) intelligence can be fully measured and quantified and b) IQ is that measure.”
It isn't The Answer to the Ultimate Question about a person.
A typical full-scale IQ score (such as given by the Wechsler tests), is called a standard score. This score corresponds to a percentile ranking of the sum of the scaled scores of selected individual subtests, which are themselves rankings of the raw scores for each task normed for each age group. It is essentially a measure of “unusualness”. The more unusual subtest scores someone has, the more that will be reflected in the sum, resulting in a more unusual full-scale score. The logic of this process can be confounded in situations where a person's scores in one area are unusually low and unusually high in another, giving the appearance of an average sum. This is why we need to look at the other composite scores (for example, Verbal or Working Memory) and the subtest scores in order to interpret the full-scale score.
In its various incarnations, IQ has been linked to certain personal characteristics and learning outcomes—I'm not going to summarize those volumes of research here. The important thing to remember when reading about such research is that statistical correlations can tell you only about the likelihood of a given outcome. They cannot be applied to individuals. We cannot know ahead of time whether a person is part of the majority who will experience a given outcome or the minority who will not. The fact that there is such a minority does not invalidate the research, just as the fact that IQ scores may be misunderstood by some does not mean they are useless or absurd.