Paul Kline reveals that the scientific basis of psychological testing is weak. He argues that truly scientific forms of measurement could be developed using measurement theory, to create a new psychometrics.

Many psychological factors are little more than statistical descriptions of particular sets of data and have no real significance. Paul Kline uses his long and extensive knowledge of psychological measurement to argue that truly scientific forms of measurement could be developed to create a new psychometrics. This would transform the basis of psychology and change it from a social science to a pure science.

'It is important reading for those who use psychological tests for real-life purposes As usual, Kline succeeds in making the issues clear and interesting I think that this is one of the most important books that he has written in recent years. It deserves to be widely read, particularly by practitioners.' - Colin Cooper, Queen's University Belfast, British Journal of Psychiatry

'This is a remarkable book by a remarkable author. It is also slim, clearly written and presented, but so full of implications for the future continuance of individual differences research, that it is at once mandatory reading for any student or faculty member who claims to be studying individual differences in the manner of an investigative scientist.' - Tom O'Connor, Institute of Psychiatry, Personality and Individual Differences

'One cannot fail to be impressed by the simplicity and clarity of the argument. Its implications for future research cannot be over-emphasised and has already ignited controversy in the field of individual differences ... This is a book that will fundamentally change the way we pursue psychological investigation - buy it and hear Kline's message.' - Cathal McCrory, Queen's University Belfast, British Journal of Educational Psychology