PSYCHOLOGICAL TESTS
ALTERNATIVE FORMS
Alternative forms of a test are ordinarily indispensable
in order to reduce the possibility of coaching or cheating.
These forms should be equal in difficulty and should correlate
 highly (over .95) with each other. The best procedure
for devising alternative forms of a test is to divide a large
list of acceptable items into several piles purely by chance.
Then by preliminary trial their actual relative difficulty
can be determined with precision.
When a battery of tests is used, the forms may, for convenience,
 be fastened together, or printed as a booklet. They
should be arranged so that only one test appears at a time,
the easiest tests at the beginning, and others following in
order of difficulty. A very easy and interesting test may be
included with no intention of scoring it but of using it
merely as a shock absorber, to put the subject at ease when
he begins. Tests which do not require timing may be placed
at the end, then the booklet may be handed in when completed.
 Instructions should specify that no one is to turn
back to a preceding test.
The construction of psychological tests for the measurement
 of abilities is a complicated matter calling for a high
degree of ingenuity and sound judgment, as well as a familiarity
 with the principles outlined in this chapter. No
amount of foresight can anticipate all the complications
which may upset a smooth-running test performance. The
investigator will find it necessary to try out his tests on a
few subjects before putting them in final form, in order to
correct unforeseen obscurities or sources of misunderstanding
 in the directions or in the body of the test.
Before treating of the problems arising in the administering
 of tests of abilities, chapters will be devoted to an instrument
 for the systematized estimation (rather than measurement)
 of abilities—the rating scale, and to an instrument
for gathering factual data—the questionnaire.

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