RELIABILITY BY DONNA MARGARET

WHAT IS RELIABILITY?  Does this test consistently measure what it’s supposed to measure?  The more similar the scores, the more reliable the test.  Not applicable to classroom-based test  Important for standardized tests

 Reliability coefficient Score between 1 and 0 The higher the score, the higher the reliability  Standard error of measurement  True score  Item Response Theory

 Stability (test re-test) - same tests are given to same subjects over a period of time - is the test stable over time? - the two scores are correlated mathematically - reliability coefficient of 1 and zero - IQ test

 Alternate forms - Form A is given to students in Texas, Form B is given to students in Arizona. - Same skills, same grade level and same subjects - Results will be correlated to get the reliability coefficient

 Internal consistency - Split half, equivalent - Same content, more items - Odd and even numbered items - Each subject get two scores

 The performance of candidates  The reliability of the scoring

 Take enough samples of behavior  Exclude items  Do not allow too much freedom  Write unambiguous items  Clear and explicit instructions  Tests are legible  Familiar with format & techniques  Uniform conditions of administration

 Objective scoring  Comparisons  Detailed scoring key  Train scorers  Outset of scoring  Identify by number, not name  Multiple, independent scoring

VALIDITY VS RELIABILITY A test may be reliable, but still it is not valid. When a test is valid, it will be reliable