An Alternate Definition of the ETS Delta Scale of Stem Difficulty
- Author(s):
-
Holland, Paul W.;
Thayer, Dorothy T.
- Publication Year:
- 1985
- Report Number:
-
RR-85-43
- Source:
-
ETS Research Report
- Document Type:
- Report
- Page Count:
- 15
- Subject/Key Words:
-
Delta Index,
Difficulty Level,
Item Analysis,
Statistical Analysis,
Test Construction
Abstract
This note develops an alternative definition of the "delta scale" of item difficulty that is used at ETS. A comparison is given with the traditional definition of the delta scale that is based on the normal distribution. Some advantages of the alternative scale are mentioned. (15pp.)
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