I__. - International Military Testing Association

discrimination values (biserials). That is, does presenting the items in other than
their normal domain and without regard to difficulty level, have an effect on the
items’ statistics? Table VI presents the average p-value changes for the common
items between the paired test administrations. The first test in each pair served as
the base item position for comparative purposes. As indicated in Table VI, the
avera e item p-values showed a somewhat greater tendency to increase (items
easier 7than
to decrease although the differences are small. The average overall
change in the items’ p-values remained quite consistent across the three pairs of test
administrations for both the BM-0110 and the EM-4613.
.’
Paired
Administrations
Table VI
Comparison of Common Items’ P-Values
Average P-Value Change By Relative Position
EM461 3
Average Overall Average Overall Average Overall
Change Increase* Decrease*
l/89 with l/90 .095 .084 .075 .107 .098
2/89 with l/89 .091 .105 .079 .092 .121
2/89 with l/90 .099 .095 .117 .087 .I12
BMOllO
l/89 with l/90
2/89 with l/89
.
.222
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.199 .055 1.199 .071
1.246 .091 I.198 .068
2/89 with l/90 .213 .227 .087 1.190 .082
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*The first column represents the average for the first test of each pair;
the second column represents the second test.
With respect to the items’ biserials, Table VII presents the average biserials for the
common items in each pair of test administrations As was the case with the pvalues,
the average biserials were quite consistent between paired test
administrations with the differences quite small.
Table VII
Average Biserials for Common Items
of Paired Test Administrations
EM-4613 BM-0110
l/89 with 2/89 .29 .25 .30 .34
l/89 with l/90 I.32 -25 1.32 .28
2/89 with l/90 .21
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278
.22
.32 .26
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