Compare methods

	Homophily Analysis	Structural Balance Theory
Field	Sociology	Sociology
Family	Process / pipeline	Process / pipeline
Year of origin	1954 (concept); 2001 (synthesis)	1946 (Heider); 1956 (Cartwright & Harary)
Originator	Lazarsfeld & Merton (concept); McPherson, Smith-Lovin & Cook (synthesis)	Fritz Heider; formalized by Dorwin Cartwright & Frank Harary
Type	Measurement of similarity-based tie formation	Theory and graph-theoretic test for tension in signed relationships
Seminal source	McPherson, M., Smith-Lovin, L., & Cook, J. M. (2001). Birds of a feather: homophily in social networks. Annual Review of Sociology, 27, 415–444.	Cartwright, D., & Harary, F. (1956). Structural balance: a generalization of Heider's theory. Psychological Review, 63(5), 277–293.
Aliases	homophily measurement, assortative mixing analysis, birds-of-a-feather analysis, tie-similarity analysis	balance theory, Heider balance, signed network balance, structural balance analysis
Related	4	5
Summary	Homophily analysis quantifies the tendency of similar individuals to form ties — the principle that 'birds of a feather flock together'. It compares the rate at which people connect with others who share an attribute (race, gender, age, education, attitudes) against what would be expected by chance, distinguishing the homophily that arises merely from group sizes from the genuine, behavior-driven preference for similar others.	Structural balance theory analyzes networks whose ties carry a sign — positive for liking, alliance, or trust, negative for hostility or distrust — and asks which configurations are psychologically and socially stable. Originating in Fritz Heider's cognitive balance principle and given a graph-theoretic form by Dorwin Cartwright and Frank Harary in 1956, it predicts that signed networks evolve toward states free of the tension produced by inconsistent triads such as 'the friend of my enemy'.