No, I was thinking of the method where you initialize the variable first, or using "recode into". I thought this method would also recode missings to 0. Thanks for pointing this out.

--- "Matheson, David" <dmatheson@SPSS.COM> wrote: > John, > I tested all of the methods in my solution with missing values > in the > categorical variable and all of them returned a missing value for > all of the > dummy variables in these cases. Do you have a counterexample? > Take the first method in the post for example. > > VECTOR nom(4). > LOOP #i = 1 to 4. > COMPUTE nom(#i) = (cat = #i). > END LOOP. > EXECUTE. > > If the expression (cat = #i) is true, a 1 is returned; if false; a > 0. If cat > is missing, then the expression can't be evaluated and the result > is system > missing. If I had initialized the dummy variables to 0 before > testing the > value of cat, then missing values on cat would have been coded as > all 0s > like the reference category. None of these methods used such an > initialization. > > There are some influence diagnostics in Regression that are not > available in > GLM or Unianova, but analysts with categorical predictors should > certainly > consider those latter options. (GLM is in the Advanced Models > module but > Unianova is in the SPSS Base module). > > David Matheson > SPSS Technical Support > > > > -----Original Message----- > From: John Hendrickx [mailto:J.Hendrickx@MAILBOX.KUN.NL] > Sent: Wednesday, November 08, 2000 4:35 AM > To: SPSSX-L@LISTSERV.UGA.EDU > Subject: Re: dummy variable > > > Unfortunately, these methods will code a missing value on the > categorical variable to 0 rather than missing on the dummies. A > workaround would be: > > temporary. > select if not missing(cat). > -- make dummies -- > regress ... > > But wouldn't it be simpler to just use GLM? > > > --- "Matheson, David" <dmatheson@SPSS.COM> wrote: > > This technical note has a few approaches to creating dummy > > variables from a > > categorical variable. You can also find it as solution 100000500 > on > > the SPSS > > AnswerNet at > > http://www.spss.com/tech/answer/index.cfm . > > > > David Matheson > > SPSS Technical Support > > > > > > Recoding a categorical SPSS variable into indicator (dummy) > > variables > > Q. > > What is the SPSS command to transform a nominal variable > > of n classification groups into a series of n-1 indicator > > (or "dummy") variables? > > > > > > A. > > Unfortunately, there is no single command to do this. There > > are several short command sequences that can do it and > > examples are provided below. Of these, the DO REPEAT > > approach is somewhat more general, or at least easier if > > the reference category is not the lowest value. > > > > * creating indicator variables. > > * all examples below generate indicators from a > > nominal variable, called cat, that is present in > > the active file. > > > > * create 4 indicator variables for categories 1 to 4 > > of a 5-category variable called cat. > > > > VECTOR nom(4). > > LOOP #i = 1 to 4. > > COMPUTE nom(#i) = (cat = #i). > > END LOOP. > > EXECUTE. > > > > * alternatively . > > * create 4 indicator variables for categories 2 to 5 > > of a 5-category variable called cat. > > > > VECTOR ind(4). > > LOOP #i = 1 to 4. > > COMPUTE ind(#i) = (cat = #i + 1). > > END LOOP. > > EXECUTE. > > > > * if you wanted to make the first category the reference > > category (0 on all indicator vars) with var names reflecting > > the original category : . > > > > NUMERIC dum2 to dum5. > > VECTOR dumv = dum2 to dum5. > > LOOP #i = 1 to 4. > > COMPUTE dumv(#i) = (cat = #i + 1). > > END LOOP. > > EXECUTE. > > > > * creating similar vars as above but using do repeat command. > > DO REPEAT iv = indv2 to indv5 > > / c = 2 to 5 . > > COMPUTE iv = (cat = c). > > END REPEAT. > > EXECUTE. > > > > * if reference category were neither first nor last, but 3rd, > > DO REPEAT seems handier than VECTOR and LOOP. > > > > DO REPEAT iv = c3i1 c3i2 c3i4 c3i5 / g = 1 2 4 5 . > > COMPUTE iv = (cat = g). > > END REPEAT. > > EXECUTE. > > > > -----Original Message----- > > From: Dirk Enzmann [mailto:enzmann@KFN-NT.KFN.UNI-HANNOVER.DE] > > Sent: Tuesday, November 07, 2000 2:31 PM > > To: SPSSX-L@LISTSERV.UGA.EDU > > Subject: Re: dummy variable > > > > > > There is no menu-option in SPSS for creating dummy variables for > > regression analyses, but there is a SPSS-macro at > > http://www.kfn.de/softwareenzmann.html > > which might do what you want. It runs fine with SPSS 6.1 but I > had > > some > > problems using it with SPSS 10 (perhaps Raynald Levesque could > have > > a > > look at it? ;-) > > > > Dirk > > > > rina <rina@NURULFIKRI.COM> wrote: > > > Is there any option in SPSS for make dummy variables for > > regression > > > analysis ? > > > and I want to know about software for Principal Component > > Regression > > > Analysis, > > > Can we use SPSS for this ? > > > >

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