1 Validity and Reliability THESIS
2 Validity u Construct Validity u Content Validity u Criterion-related Validity u Face Validity
3 Construct Validity Is the underlying construct or theoretical foundation of the survey consistent with research and information on the topic?
4 Content Validity Does the content of the items in the instrument accurately reflect the underlying construct?
5 Criterion-related Validity Does the instrument contain the proper criteria for measuring the traits or constructs of interest?
6 Face Validity Does the instrument look like it will measure what it is supposed to measure?
7 Reliability u Test - Retest u Alternative forms u Split halves u Internal consistency
8 Test - Retest Method u Administer instrument u Analyze responses u Administer instrument again under exact conditions u Correlate responses
9 Alternative Forms Method u Administer instrument u Analyze responses u Administer different form of same survey u Correlate responses
10 Split Halves Method u Administer instrument u Separate responses by odd and even items u Correlate two halves u Correct using Spearman-Brown
11 Internal Consistency (Cronbach’s Alpha) u Administer instrument u Compute inter-item correlation matrix u Compute mean inter-item correlation u Enter alpha formula
12 Question Can a survey be: Valid but not reliable? Reliable but not valid?