The research support for the authors strategy is weak but the book is worth buying for the wisdom it contains on risk, insiders, and investor psychology. Inexperienced investors could find themselves stranded when implementing the books' often subjective sell criteria.
One of the authors admit to having to give up part of their occupations to write the book, it shows. Is this book really a value investing book in disguise? Take out one rule about stocks being down 50% and you are left with a book on insiders and low P/E investing.
There is an absense of any testing of the final recommended set of rules. A clue as to why is when the authors admit that in September 1996 only a handful of stocks met their recommended strategy criteria.
Where is the authors own performance following thier criteria?
The research cited in the book is only on each core components of their purchase criteria but not on the combination, or risk management rules or acombination thereof, and therfore claiming the whole is suported by the research is a giant leap.
This lack of research leaves many questions unanswered. How did their strategy do with gold stocks, or steel stocks, which have been contrarian plays for years? What would have happened to their strategy in this raging growth stock bull market?
The authors too often fir example of their strategy by making exceptions to their rules by using subjective analysis and hindsight: such as "when the company's prospects are clearly improving, when the stock price seems to be climbing a 'wall of worry.'"
Too often the authors use the words "often", "can". which are useless as rules or criteria. Too often the authors contradict themselves.
However the good sections on risk, investor psychology make it worthwhile reading.