This is the continuation of chapter 16- accuracy and error.

1. EDUC 243 EDUCATIONAL EVALUATION
ACCURACY AND ERROR
Reporter: Marilou T. Magdula

2. Why all the fuss about
error?
• For two reasons:
1. We want to make you aware of the
fallibility of test scores.
2. We want to sensitize you to the
factors that can affect scores.

3. Classification of sources of
error
1. Test takers
2. The test itself
3. Test administration
4. Test scoring

4. Test Takers:
• Factors that would likely result in an
obtained score lower that a student’s
true score:
• Fatigue and illness
• Accidentally seeing another student’s
answer

5. The test itself:
• Trick questions
• Reading level that is too high.
• Ambiguous questions
• Items that are too difficult.

6. Test Administration
• Physical Comfort
• Instructions and Explanations
• Test Administrators Attitudes

7. Error in Scoring:
• When computer scoring is used,
error can occur.
• When test are hand scored, the
likelihood of error increases greatly.

8. Sources of Error Influencing
Various Reliability
Coefficients
• Test-Retest
• Alternate Forms
• Internal Consistency

9. Test- Retest
• Short-interval test-retest coefficients are
not likely to be affected greatly by within-
student error.
• Any problem that do exist in the test are
present both the first and the second
administrations, affecting scores the
same way each time the test is
administered.

10. Alternate Form
• Since alternate forms reliability is
determined by administering two
different forms or versions of the same
test to the same group close together in
time, the effects within student error are
negligible.

11. Alternate Form
• Error within the test, however, has a
significant effect on alternate-forms
reliability.
• As with test-retest methods, alternate
forms score reliability is not greatly
affected by error in administering or
scoring the test, as long as similar
procedures are followed.

12. Band Interpretation
• Uses the standard error of
measurement to a more realistic
interpretation and report groups
of test scores.

13. Thank You and God Bless!!!