# Tobit estimation?

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## Tobit estimation?

 Folks, Based on   http://www.biostat.wustl.edu/archives/html/s-news/1999-06/msg00125.htmlI thought I should experiment with using survreg() to estimate tobit models. I start by simulating a data frame with 100 observations from a tobit model > x1 <- runif(100) > x2 <- runif(100)*3 > ystar <- 2 + 3*x1 - 4*x2 + rnorm(100)*2 > y <- ystar > censored <- ystar <= 0 > y[censored] <- 0 > D <- data.frame(y, x1, x2) > head(D)           y         x1        x2 1 0.0000000 0.86848630 2.6275703 2 0.0000000 0.88675832 1.7199261 3 2.7559349 0.38341782 0.6247869 4 0.0000000 0.02679007 2.4617981 5 2.2634588 0.96974450 0.4345950 6 0.6563741 0.92623096 2.4983289 > # Estimate it > library(survival) > tfit <- survreg(Surv(y, y>0, type='left') ~ x1 + x2,                   data=D, dist='gaussian', link='identity') It says:   Error in survreg.control(...) : unused argument(s) (link ...)   Execution halted My competence on library(survival) is zero. Is it still the case that it's possible to be clever and estimate the tobit model using library(survival)? I also saw the two-equation setup in the micEcon library. I haven't yet understood when I would use that and when I would use a straight estimation of a censored regression by MLE. Can someone shed light on that? My situation is: Foreign investment on the Indian stock market. Lots of firms have zero foreign investment. But many do have foreign investment. I thought this is a natural tobit situation. -- Ajay Shah                                      http://www.mayin.org/ajayshah  [hidden email]                             http://ajayshahblog.blogspot.com<*(:-? - wizard who doesn't know the answer. ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide! http://www.R-project.org/posting-guide.html