1. Chapter 11: Measuring Research Variables
SFM 651:
Research Methods
Dr. Johnson

2. Validity
The degree to which a test or instrument measures what it is supposed to measure
Logical – degree to which the measure obviously involves the performance being measured.
Valid by definition
Also called face validity
Content – degree to which the test adequately samples what was being covered
Usually educational
Exam in class

3. Validity
Criterion – degree to which scores on a test are related to some recognized standard
MAP test
Olympic Figure skating judges
Predictive – can predict scores
Construct - degree to which a test measures a hypothetical construct
Looking at things that cant be observed
Anxiety, creativity, attitude

4. Reliability The consistency or repeatability of a study
If we do the same things again, will we get the same result?
Ranges from 0.00 to 1.00
Closer to 0.00 means more error
Closer to 1.00 means less error
Intertester reliability
Will the same tester get the same scores when observed.

5. ANOVA Analysis of Variance – called ANOVA
Most common type of statistical analysis
Looks at the Null hypothesis
Tests the differences between two means
General differences, not specific
Often used in Reliability studies.

6. Stability
Coefficient of reliability measured by the test-retest method on different days
Will the same result occur again?
More used on fitness tests
Not so much on paper and pencil tests

7. Standard Measure of Error
Scores fall within a range
Standard Deviation * Square root (1.00-r)
22.4% ± 2.3%

8. Z Scores
Basic standard score that converts raw scores to units of standard deviation in which the mean is 0 and SD is 1.
Can compare 2 tests easily
Vertical jump and push-ups

9. T-Scales
Type of Standard score that sets the mean at 50 and standard Deviation at 10 to remove the decimal found in z scores and to make all scores positive.
1 SD above the mean = = 60
1 SD below the mean = = 40

10. Likert Scales
Type of closed question that requires choosing from one of several scaled responses
Usually 1-5 or 1-10 if number
Usually strongly agree to strongly disagree is words

11. Errors Central tendencies error
Raters give more scores in the middle.
Observer Bias Error – expecting a certain response
Halo effect – previous impressions influence ratings