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COM 633: Content Analysis Reliability. Kimberly A. Neuendorf, Ph.D. Cleveland State University Fall 2010. Reliability. Generally—the extent to which a measuring procedure yields the same results on repeated trials (Carmines & Zeller, 1979) Types: Test-retest: Same people, different times.
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COM 633: Content AnalysisReliability Kimberly A. Neuendorf, Ph.D. Cleveland State University Fall 2010
Reliability • Generally—the extent to which a measuring procedure yields the same results on repeated trials (Carmines & Zeller, 1979) • Types: • Test-retest: Same people, different times. • Intracoder reliability. . . • Alternative-forms: Different people, same time, different measures. • Internal consistency: Multiple measures, same construct. • Inter-rater/Intercoder: Different people, same measures.
Index/Scale Construction • Similar to survey or experimental work • e.g., Bond analysis—Harm to female, sexual activity • Need to check internal consistency reliability (e.g., Cronbach’s alpha)
Intercoder Reliability • Defined: The level of agreement or correspondence on a measured variable among two or more coders • What contributes to good reliability? careful unitizing, codebook construction, coder training (training, training!)
Reliability Subsamples • Pilot and Final reliability subsamples • Because of drift, fatigue, experience • Selection of subsamples • Random, representative subsample • “Rich Range” subsample • Useful for “rare event” measures • Reliability/variance relationship
Reliability Statistics - 1 • Types • Agreement • Agreement beyond chance • Covariation • Core assumptions of coefficients • “More scholarship is needed”—these coefficients have not been assessed!
Reliability Statistics - 2 • My recommendations • Do NOT use percent agreement ALONE • Nominal/Ordinal: Kappa (Cohen’s, Fleiss’) • Interval/Ratio: Lin’s concordance • Calculated via PRAM • Reliability analyses as diagnostics, e.g., • Problematic variables, coders (“rogues”?), variable/coder interactions • Confusion matrixes (categories that tend to be confused)
PRAM: Program for Reliability Analysis with Multiple Coders • Written by rocket scientists! • Trial version available from Dr. N!