השוואת שיטות

	UNIDIFF Mobility Model	Log-Linear Mobility Model
תחום	Sociology	Sociology
משפחה	Regression model	Regression model
שנת המקור	1992	1970s
הוגה השיטה	Yu Xie; Robert Erikson & John Goldthorpe (parallel)	Leo Goodman; Robert Hauser
סוג	Log-multiplicative model for comparing association across tables	Log-linear / Poisson model for cell counts in mobility tables
מקור מכונן	Xie, Y. (1992). The log-multiplicative layer effect model for comparing mobility tables. American Sociological Review, 57(3), 380–395.	Hauser, R. M. (1978). A structural model of the mobility table. Social Forces, 56(3), 919–953.
כינויים	UNIDIFF model, log-multiplicative layer effect model, uniform difference model, Xie-Erikson-Goldthorpe model	log-linear model for mobility, topological mobility model, quasi-independence model, levels model
קשורות	4	5
תקציר	The uniform difference (UNIDIFF) model, equivalently the log-multiplicative layer effect model, compares the strength of origin–destination association across several mobility tables — countries, time periods, or birth cohorts. It assumes the tables share a common pattern of association ψ_ij but allows the overall strength of that pattern to differ by a single layer-specific multiplier φ_k. A φ_k above one means stronger origin effects (less fluidity) in that layer; below one means greater fluidity.	Log-linear mobility models analyze an origin-by-destination mobility table by modeling the logarithm of its expected cell counts as a sum of terms: separate effects for the origin and destination marginals plus interaction terms that capture the origin–destination association. By specifying that association parametrically — through diagonal, level, or scaled terms — these models test precise hypotheses about the structure of social fluidity independent of the changing sizes of classes.