Fig. 1
Number of items re-used two-, three-, and four-times in a five year period
Table 1
Average difficulty and discrimination coefficients per number of time questions were used
|
Average difficulty (standard deviation) |
Average discrimination (standard deviation) | |||||
|---|---|---|---|---|---|---|
|
Number of uses |
2 |
3 |
4 |
2 |
3 |
4 |
|
N |
1,182 |
364 |
83 |
1,102 |
349 |
80 |
|
1st use |
80.18 (17.69) |
79.13 (16.85) |
78.06 (18.30) |
0.173 (0.114) |
0.165 (0.115) |
0.184 (0.104) |
|
2nd use |
81.69 (17.13) |
83.80 (16.18) |
80.18 (18.82) |
0.171 (0.114) |
0.141 (0.111) |
0.149 (0.115) |
|
3rd use |
84.48 (15.94) |
84.31 (14.25) |
0.135 (0.107) |
0.149 (0.126) | ||
|
4th use |
84.92 (14.77) |
0.140 (0.115) | ||||
|
p value |
<0.0001 |
<0.0001 |
<0.0001 |
0.227 |
<0.0001 |
0.004 |