Hi all,

there is a new package called -udiff- available from SSC. It can be used to estimate so-called "unidiff" (Erikson and Goldthorpe 1992) or "log-multiplicative layer effect" models (Xie 1992) that are popular in sociological analyses of intergenerational status mobility. -udiff- operates at the level of individual observations, not at the aggregate level of mobility tables, supports survey estimation, and is more general than the unidiff implementation by Pisati (2000) in the sense that (1) multiple, and possible continuous origin variables, (2) multiple, and possible continuous layer variables, and (3) multiple unidiff components can be included in the model. To install the command, type
Code:
. ssc install udiff, replace
Best, ben

PS: The command has been available from SSC since last November, but it has now received an update fixing some bugs and expanding functionality.

References:
Erikson, R., J.H. Goldthorpe. 1992. The Constant Flux: A Study of Class Mobility in Industrial Societies. Oxford: Oxford University Press.
Pisati, M. 2000. sg142: Uniform layer effect models for the analysis of differences in two-way associations. Stata Technical Bulletin 55: 33-47.
Xie, Y. 1992. The Log-Multiplicative Layer Effect Model for Comparing Mobility Tables. American Sociological Review 57(3): 380–395.