Validity and Reliability THESIS

Validity u Construct Validity u Content Validity u Criterion-related Validity u Face Validity

Construct Validity Is the underlying construct or theoretical foundation of the survey consistent with research and information on the topic?

Content Validity Does the content of the items in the instrument accurately reflect the underlying construct?

Criterion-related Validity Does the instrument contain the proper criteria for measuring the traits or constructs of interest?

Face Validity Does the instrument look like it will measure what it is supposed to measure?

Reliability u Test - Retest u Alternative forms u Split halves u Internal consistency

Test - Retest Method u Administer instrument u Analyze responses u Administer instrument again under exact conditions u Correlate responses

Alternative Forms Method u Administer instrument u Analyze responses u Administer different form of same survey u Correlate responses

Split Halves Method u Administer instrument u Separate responses by odd and even items u Correlate two halves u Correct using Spearman-Brown

Internal Consistency (Cronbach’s Alpha) u Administer instrument u Compute inter-item correlation matrix u Compute mean inter-item correlation u Enter alpha formula

Question Can a survey be: Valid but not reliable? Reliable but not valid?