January 13, 2011
2010 was quite an eventful year for SMR: Our cover got a new look, we published a special issue on sequence analysis, welcomed new members to the Editorial Board, and, most important, launched the SMR blog.
Thompson-Reuters released the 2009 Journal Citation Reports, and SMR had a very strong showing. For 2010, Thompson-Reuters introduced the 5-year impact factor, a major improvement over its previous measure which was overly sensitive to short term changes. Sociological Methods & Research ranked #4 among top sociology journals according to the new measurement, just behind ARS, AJS and ASR. In addition, SMR is #5 among social science methods journals.
2011 so far seems to be just as promising! Read the rest of this entry »
February 7, 2010
McDonald and Moffitt’s (1980) decomposition method for Tobit coefficients disaggregates the total changes in a censored outcome variable into the changes in the probability of attaining noncensored values and the changes in the noncensored values themselves. McDonald and Moffitt, however, did not highlight two limitations of this decomposition, and sociological applications of the Tobit decomposition that do not acknowledge these limitations have been misleading. First, the decomposition ratio of the two effects depends on the choice of an observation point in the sample. Some sociological studies invalidly generalized a decomposition at the mean point of the sample to the whole sample. Second, once the observation point is fixed, the decomposition ratio is the same across all coefficients or across all predictors. That is, the two effects remain proportionally constant, but studies often erroneously assume they differ across predictors. Further implications are discussed in relation to other selection bias models.
Key Words: Tobit • decomposition • methodology • selection model