Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
From | "Borgomeo, Letizia" <L.Borgomeo@warwick.ac.uk> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | R: st: cmogram command for Regression Discontinuity Design |
Date | Mon, 5 Sep 2011 19:37:21 +0000 |
Thank you very much, that's exactly what I was looking for. Letizia ________________________________________ Da: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] per conto di Nick Cox [njcoxstata@gmail.com] Inviato: lunedì 5 settembre 2011 21.19 A: statalist@hsphsun2.harvard.edu Oggetto: Re: st: cmogram command for Regression Discontinuity Design You can just superimpose -twoway- calls. sysuse auto, clear scatter mpg weight || lfit mpg weight if weight < 3000 || lfit mpg weight if weight >= 3000 , /// legend(order(2 "weight < 3000" 3 "weight >= 3000")) A more general idea is to use -line- calls with different predictions. Nick 2011/9/5 Borgomeo, Letizia <L.Borgomeo@warwick.ac.uk>: > In my special case, 0 does indeed belong to small positives since it is the result of the transformation of the original score for having it centered in 0. So 0 it is the mimimum score for individuals(firms) to get the treatment(public subsidy).Honestly, the reason why I started using -cmogram- is that I am not aware of a way of plotting two different fitlines for each side of the cutoff. > ________________________ > Da: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] per conto di Nick Cox [njcoxstata@gmail.com] > Inviato: lunedì 5 settembre 2011 20.36 > A: statalist@hsphsun2.harvard.edu > Oggetto: Re: st: cmogram command for Regression Discontinuity Design > > We do ask that all new joiners read the FAQ before posting. > > As implied, you can also fudge your 0s to small positives so that they > fall within the right bin (so to speak). Otherwise your graph won't > show a cutpoint at 0, which is important for your problem. But you'd > need to fudge all boundary values consistently. > > Personally I like the convention that bins are as far as possible > [lower, upper) but -cmogram- follows the opposite rule. > > The choice may seem arbitrary, but in most problems I look at it seems > more natural that 0 is not only a bin boundary but belongs with small > positives rather than small negatives. The substantive reason is often > that 0 may just mean not detected, but negatives mean something > different. But problems and tastes vary. > > By the way, -cmogram- is just a convenience command. It is just a > couple of lines to set up bins that you like and summaries for those > bins, e.g. > > sysuse auto > gen weight2 = 500 * floor(weight/500) > egen mean = mean(mpg), by(weight2) > > after which you call up some graph of choice. > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/