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From | Nick Cox <njcoxstata@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: cascading dummies |
Date | Mon, 1 Oct 2012 20:15:50 +0100 |
As Richard said, Stata can tell you: . findit cascade STB-6 srd11 . . . . . . . . . Generating ordered "cascading" dummy variables (help cascade if installed) . . . . . . . . . . . . . . . R. Goldstein 3/92 pp.19--22; STB Reprints Vol 1, pp.190--194 add a set of new dummy variables that are cascading; that is, 0/1 variables are created where a 1 is given if the case has the value <= value of lowest category Accessible at http://www.stata.com/products/stb/journals/stb6.pdf Nick On Mon, Oct 1, 2012 at 7:59 PM, Shikha Sinha <shikha.sinha414@gmail.com> wrote: > Thanks Richard! > > very helpful. What is the full reference of STB article, I am unable to find it. On Mon, Oct 1, 2012 at 11:39 AM, Richard Goldstein > <richgold@ix.netcom.com> wrote: >> neither is wrong or right -- they answer slightly different questions; A >> asks for each dummy whether, and by how, much it is different from the >> reference group (you do realize that you should only include 4 of the >> dummies, right?); B asks whether each differs from the preceding level >> >> you can -findit cascade- to find a program I wrote to implement >> cascading dummies; the help file, and even more the STB article, >> discusses the differences; note that you can obtain the answer to either >> question by following up the original method of forming the variables >> with the appropriate -test- command(s) On 10/1/12 2:31 PM, Shikha Sinha wrote: >>> Recently, I came across a new way of creating dummies and I wonder >>> what the group thinks about this form. >>> >>> The independent variable X is coded as 1- very poor, and 5 as very >>> rich. I want to estimate the effect by wealth quintile. I created the >>> dummy the following ways, but I was told that this is wrong (A is >>> wrong). The correct way to construct dummy is B and is called >>> cascading dummies. I have never come across this before and would >>> appreciate if you could shed light on the difference between the two >>> and which is the correct way of creating dummies. >>> >>> A: >>> id Y X1 (scale of 1-5), dum1 dum2 dum3 dum4 dum5 >>> 1 100 5 0 0 0 0 1 >>> 2 200 4 0 0 0 1 0 >>> 3 300 3 0 0 1 0 0 >>> 4 239 2 0 1 0 0 0 >>> 5 345 1 1 0 0 0 0 >>> >>> >>> B: >>> id Y X1 (scale of 1-5), dum1 dum2 dum3 dum4 dum5 >>> 1 100 5 1 1 1 1 1 >>> 2 200 4 1 1 1 1 0 >>> 3 300 3 1 1 1 0 0 >>> 4 239 2 1 1 0 0 0 >>> 5 345 1 1 0 0 0 0 * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/