The standardized educational or psychological tests that are widely used to aid inselecting，classifying，assigning，or promoting students，employees，and military personnelhave been the target of recent attacks in books，magazines，the daily press，and even inCongress.（71）The target is wrong，for in attacking the tests，critics divert attentionfrom the fault that lies with illinformed or incompetent users.The tests themselves aremerely tools，with characteristics that can be measured with reasonable precision underspecified conditions.Whether the results will be valuable，meaningless，or even misleadingdepends partly upon the tool itself but largely upon the user.

All informed predicitions of future performance are based upon some knowledge ofrelevant past performance:school grades，research productivity，sales records，orwhatever is appropriate.（72）How well the predictions will be validated by laterperformance depends upon the amount，reliability，and appropriateness of theinformation used and on the skill and wisdom with which it is interpreted.Anyone whokeeps careful score knows that the information available is always incomplete and that thepredictions are always subject to error.

Standardized tests should be considered in this context.They provide a quick objectivemethod of getting some kinds of information about what a person learned，the skills he hasdeveloped，or the kind of person he is.The information so obtained has，qualitatively，thesame advantages and shortcomings as other kinds of information.（73）Whether to usetests，other kinds of information，or both in a particular situationdepends，therefore，upon the evidence from experience concerning comparativevalidity and upon such factors as cost and availability.

（74）In general，the tests work most effectively when the qualities to bemeasured can be most precisely defined and least effectively when what is to bemeasured or predicated can not be well defined.Properly used，they provide a rapid meansof getting comparable information about many people.Sometimes they identify studentswhose high potential has not been previously recognized，but there are many things they donot do.（75）For example，they do not compensate for gross social inequality，andthus do not tell how able an underprivileged youngster might have been had he grownup under more favorable circumstances.