Open AccessESTIMATING TEST RELIABILITY
Author(s) -
Lord Frederic M.
Publication year - 1955
Publication title -
ets research bulletin series
Language(s) - English
Resource type - Journals
eISSN - 2333-8504
pISSN - 0424-6144
DOI - 10.1002/j.2333-8504.1955.tb00054.x
Subject(s) - reliability (semiconductor) , parallelism (grammar) , test (biology) , standard error , mathematics , statistics , computer science , algorithm , reliability engineering , parallel computing , engineering , power (physics) , paleontology , quantum mechanics , biology , physics
Formulas for parallel‐form reliability coefficients are derived from two improved definitions of parallelism. One definition, based on randomly parallel test forms, leads to a new and useful derivation for the KR formula‐21 coefficient. The other, based on matched test forms, leads to a formula for the least upper bound of the test reliability. A numerical example is given, showing how a standard error of measurement for each separate examinee is readily computed, and how the test reliability may be computed by averaging these standard errors.