Technical Report - International Military Testing Association

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Item ~nalyrie Information for Test Revision
VERN w. URRY
US Arwy Enlisted Evaluation Center
The item aMly8is coding procedures used at the US Army Enlisted
Evaluation Center represent an application of Cullikren’e item &leCtion
techniques to MOS Evaluation Test redevelopment. These techniques were
advanced by Culliksen (1950) in his “Theory of Mental Tests.” They call
for the use in item anrrlyeis of the point-biaerial correlation coefficient.
Ws are currently using thir statistic for that purpose.
XtCcP analysis codes are provided to indicate appropriate actions to
be taken by item writers in regard to individual HOS evaluation test items.
While a full explanation of the 8 Codes used vi11 not be given, the present
paper will discuer the statistlcal bases for theme action code8 vhich have
to do vith the selection of acceptable item or the revision of items
needing minor changer. The advantage8 fn improved measurement3 to be
gained by the implementation of these particular action code8 will al80
be dircusscd.
Basically, item analysis has am its purpose the development of a
test vith a given set of statistical chararteristica either through
item eelectioa or item revisfoa. For a lOO-item HOS Evaluation Test,
the deeired set of statistical characterietice vould include a mean of
62.5, a standard devtatioa of 12.5, and a reliability of .80 a6 a mFaimum.
The desired mean equally divides the range from a chance score of 25
to a mxinarm or perfect score of 100, and the derlred 1taadard deviation
io determined by dividing 6 into the above range, since 3 atanda:d
deviations on c ither side of the mean cmtaine, for all practical purposes,
a normal dictribution. The chance scora ir a function of the fact that
each l4m Evaluation Tec;t Item contains 4 plausible alterridtives; hence,
if OM were guessing 11’4 or 25 of the item would, on the average, be
msvered correctly.
The it- analysis action codas to be useJ by iteta writers take
into account the dcrlred set of statistical characteristica for NO!3
Evaluation Tests and the item statistics required to cbtafn HOS Evaluation
Tart8 vith these atatirtical characttrirtics. Item rtatisticr relate to
the statistical characterirticr of a teat in the following annner
(Culliksen, 1951):
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