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From | Arne Risa Hole <arnehole@gmail.com> |
To | statalist <statalist@hsphsun2.harvard.edu> |
Subject | Re: st: example about choice experiment datasheet |
Date | Mon, 26 Nov 2012 11:42:41 +0000 |
This is to be expected; if you found it surprising you need to read the -asclogit- manual entry more carefully. Whether it's correct or not really depends on what you are trying to do. I would suggest that including socio-demographics in your model only makes sense if you interact them with the alternative-specific attributes, since your alternatives are unlabelled. Arne On 26 November 2012 10:43, elisabetta capobianco <elisabetta.capobianco@gmail.com> wrote: > Ok Arne, > now It's clear and I have had good results. > Just a doubt. When I put inside the socio-demographic variables, the > output has the four alternatives 1,2,3,4, even if I write nocons. > I don't understand the meaning of this output considering that I have > unlabelled alternatives. > Is however correct this result? > > Thank you, > Elisabetta > > > > > > 2012/11/24 Arne Risa Hole <arnehole@gmail.com>: >> Elisabetta, >> >> The "case" variable must a unique identifier for each choice. You can >> generate it like this >> >> egen caseid = group(id scenario) >> >> The "alt" variable should be coded 1,2,3,4,1,2,3,4 etc. (not >> 1,2,3,4,5,6,7,8,...). >> >> Arne >> >> On 24 November 2012 16:04, elisabetta capobianco >> <elisabetta.capobianco@gmail.com> wrote: >>> Thank you Arne, I have taken the book. >>> My problem is that I have 16 scenarios for id (n=131) with 4 different >>> alternatives for each scenario . >>> So in the dataset I have written for each id non 4 alternatives >>> (1,2,3,4) but 64 alternatives. Is it correct? >>> >>> >>> >>> id scenario alt >>> 1 1 1 >>> 1 1 2 >>> 1 1 3 >>> 1 1 4 >>> 1 2 5(or1?) >>> 1 2 6(or2?) >>> 1 2 7(or3?) >>> 1 2 8 (or4?) >>> 1 3 9(or1?) >>> . >>> . >>> . >>> . >>> . >>> 1 16 64 >>> 2 1 1 >>> . >>> . >>> And when I wrote: >>> asclogit choice organic price, case(id) alternatives(car) noconst >>> >>> case is id or scenario? I suppose scenario. But if is scenario I don't >>> know how to use id! >>> And alternatives are the 64 alternatives? >>> >>> >>> Thank you so much for your help. >>> >>> elisabetta >>> >>> >>> >>> >>> >>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>: >>>> Elisabetta >>>> >>>> I am fairly sure that you can use -asclogit- to do what you want. If >>>> you don't want alternative-specific constants you can use the >>>> -noconst- option. Modifying the example in the help-file slightly: >>>> >>>> webuse choice >>>> asclogit choice dealer, case(id) alternatives(car) noconst >>>> >>>> As you can see the only coefficient which is estimated in this case is >>>> the one for the dealer attribute, which is analogous to the organic >>>> and price attributes in your experiment. In your case the variable >>>> that identifies the alternatives for each case ("car" in the example) >>>> can simply take the values 1, 2, 3 and 4 since your alternatives are >>>> unlabelled. >>>> >>>> I also recommend taking a look at a basic choice modelling text before >>>> proceeding, such as >>>> http://books.google.co.uk/books/about/Applied_Choice_Analysis.html?id=8yZrtCCABAgC. >>>> >>>> Good luck! >>>> >>>> Arne >>>> >>>> On 23 November 2012 13:25, elisabetta capobianco >>>> <elisabetta.capobianco@gmail.com> wrote: >>>>> I think that asclogit is not the right comand for me. >>>>> Because I have 4 unlabeled alternatives, 16 diferrent scenarios with 4 >>>>> alternatives for 131 individuals. So my indipendent viariables are the >>>>> attributes and dipendent variables the utility for each level of >>>>> attribute. >>>>> I need to know the importance of every level, not of alternatives. >>>>> Ex.:n=131 >>>>> scenario 1) A B C D >>>>> organic org no org no org org >>>>> price 4 8 4 4 >>>>> scenario 2) A B C D >>>>> organic no org no org org no org >>>>> price 12 16 8 8 >>>>> . >>>>> . >>>>> . >>>>> Perhaps with mixlogit? Because the example is on a specific >>>>> alternative, car or bus. >>>>> I instead need to know the coefficient of attributes and levels. >>>>> >>>>> I don't know if I have explained well, I hope! >>>>> >>>>> e >>>>> >>>>> >>>>> >>>>> 2012/11/23 Arne Risa Hole <arnehole@gmail.com>: >>>>>> -help asclogit_postestimation- >>>>>> >>>>>> Arne >>>>>> >>>>>> On 23 November 2012 11:05, elisabetta capobianco >>>>>> <elisabetta.capobianco@gmail.com> wrote: >>>>>>> Dear Arne, >>>>>>> i need to estimate the marginal effect of levels on attributes of my choice. >>>>>>> Is it possible? >>>>>>> es: >>>>>>> about meat: >>>>>>> attribute level >>>>>>> label organic/not organic >>>>>>> origin local abroad >>>>>>> prize 4/8 >>>>>>> >>>>>>> I would know the utility for each level of each attribute. >>>>>>> >>>>>>> Thank you! >>>>>>> elisabetta >>>>>>> >>>>>>> >>>>>>> >>>>>>> 2012/11/21 elisabetta capobianco <elisabetta.capobianco@gmail.com>: >>>>>>>> Thank you so much Arne!!! >>>>>>>> I'm creating the data set and then i'll try to run in Stata! >>>>>>>> >>>>>>>> Elisabetta >>>>>>>> >>>>>>>> 2012/11/20 Arne Risa Hole <arnehole@gmail.com>: >>>>>>>>> Elisabetta >>>>>>>>> >>>>>>>>> -mlogit- is not very useful to model data from choice experiments as >>>>>>>>> it does not allow alternative-specific explanatory variables. >>>>>>>>> -asclogit- requires your data to be in long form (one row per >>>>>>>>> alternative); see -help asclogit- and the first example in the paper I >>>>>>>>> mentioned in my last email. >>>>>>>>> >>>>>>>>> Arne >>>>>>>>> >>>>>>>>> On 20 November 2012 10:04, elisabetta capobianco >>>>>>>>> <elisabetta.capobianco@gmail.com> wrote: >>>>>>>>>> Thank you Arne, I want to use asclogit and mlogit for my choice modelling. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> 2012/11/19 Arne Risa Hole <arnehole@gmail.com>: >>>>>>>>>>> Elisabetta >>>>>>>>>>> >>>>>>>>>>> As Jay says the correct data form depends on the estimation command >>>>>>>>>>> you are planning to use, so this is a very important piece of >>>>>>>>>>> information that you haven't given us. You may find the examples in >>>>>>>>>>> http://www.stata-journal.com/article.html?article=st0133 useful. >>>>>>>>>>> Generally speaking the best strategy is to import the data into Stata >>>>>>>>>>> and then use commands like -reshape- to convert the data into the form >>>>>>>>>>> you want, rather than trying to do this in Excel. >>>>>>>>>>> >>>>>>>>>>> Arne >>>>>>>>>>> >>>>>>>>>>>> On 19 November 2012 15:51, elisabetta capobianco >>>>>>>>>>>> <elisabetta.capobianco@gmail.com> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> Thank you for your answer! >>>>>>>>>>>>> I want to do a mixed logit, but I have found a data set on help file >>>>>>>>>>>>> with just one choice set. I have 16 choice sets and I don't know how >>>>>>>>>>>>> to fil the excel data set. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> 2012/11/18 JVerkuilen (Gmail) <jvverkuilen@gmail.com>: >>>>>>>>>>>>> > On Sun, Nov 18, 2012 at 4:11 AM, elisabetta capobianco >>>>>>>>>>>>> > <elisabetta.capobianco@gmail.com> wrote: >>>>>>>>>>>>> >> Hi, I'm new of statalist and stata! >>>>>>>>>>>>> >> I'm working on choice experiment about food preferences in schools. >>>>>>>>>>>>> >> I have 4 alternatives unlabelled, 4 attributes and 4 levels, 130 >>>>>>>>>>>>> >> individuals. >>>>>>>>>>>>> >> I have the data base in excel, but before insheet the file in stata >>>>>>>>>>>>> >> i'm not sure that i have put the data in the right mode in the excel >>>>>>>>>>>>> >> file. >>>>>>>>>>>>> >> Have you got an example on a excel datasheet about choice modelling? >>>>>>>>>>>>> >> Just an example to understand how to organize my datasheet. >>>>>>>>>>>>> > >>>>>>>>>>>>> > It depends on what analysis you want to use. -clogit- and procedures >>>>>>>>>>>>> > like it that are using alternative-specific predictors use the same >>>>>>>>>>>>> > basic format, which is specified in the help file. You can see the >>>>>>>>>>>>> > example dataset there. Essentially it is a "long" format like >>>>>>>>>>>>> > person-period in a growth model with time-varying covariates. >>>>>>>>>>>>> > * >>>>>>>>>>>>> > * 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/ >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> -- >>>>>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Le informazioni contenute in questa comunicazione e gli >>>>>>>>>>>>> eventuali documenti allegati >>>>>>>>>>>>> >>>>>>>>>>>>> hanno carattere confidenziale e sono a uso esclusivo del >>>>>>>>>>>>> destinatario. Nel caso >>>>>>>>>>>>> >>>>>>>>>>>>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>>>>>>>>>>>> che la sua diffusione >>>>>>>>>>>>> >>>>>>>>>>>>> e riproduzione è contraria alla legge e prego di darmi >>>>>>>>>>>>> prontamente avviso >>>>>>>>>>>>> >>>>>>>>>>>>> e di cancellare quanto ricevuto. Grazie. >>>>>>>>>>>>> >>>>>>>>>>>>> * >>>>>>>>>>>>> * 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/ >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> * >>>>>>>>>>> * 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/ >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Le informazioni contenute in questa comunicazione e gli >>>>>>>>>> eventuali documenti allegati >>>>>>>>>> >>>>>>>>>> hanno carattere confidenziale e sono a uso esclusivo del >>>>>>>>>> destinatario. Nel caso >>>>>>>>>> >>>>>>>>>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>>>>>>>>> che la sua diffusione >>>>>>>>>> >>>>>>>>>> e riproduzione è contraria alla legge e prego di darmi >>>>>>>>>> prontamente avviso >>>>>>>>>> >>>>>>>>>> e di cancellare quanto ricevuto. Grazie. >>>>>>>>>> >>>>>>>>>> * >>>>>>>>>> * 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/ >>>>>>>>> >>>>>>>>> * >>>>>>>>> * 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/ >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Le informazioni contenute in questa comunicazione e gli >>>>>>>> eventuali documenti allegati >>>>>>>> >>>>>>>> hanno carattere confidenziale e sono a uso esclusivo del >>>>>>>> destinatario. Nel caso >>>>>>>> >>>>>>>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>>>>>>> che la sua diffusione >>>>>>>> >>>>>>>> e riproduzione è contraria alla legge e prego di darmi >>>>>>>> prontamente avviso >>>>>>>> >>>>>>>> e di cancellare quanto ricevuto. Grazie. >>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>>>>>> >>>>>>> >>>>>>> >>>>>>> Le informazioni contenute in questa comunicazione e gli >>>>>>> eventuali documenti allegati >>>>>>> >>>>>>> hanno carattere confidenziale e sono a uso esclusivo del >>>>>>> destinatario. Nel caso >>>>>>> >>>>>>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>>>>>> che la sua diffusione >>>>>>> >>>>>>> e riproduzione è contraria alla legge e prego di darmi >>>>>>> prontamente avviso >>>>>>> >>>>>>> e di cancellare quanto ricevuto. Grazie. >>>>>>> >>>>>>> * >>>>>>> * 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/ >>>>>> >>>>>> * >>>>>> * 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/ >>>>> >>>>> >>>>> >>>>> -- >>>>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>>>> >>>>> >>>>> >>>>> Le informazioni contenute in questa comunicazione e gli >>>>> eventuali documenti allegati >>>>> >>>>> hanno carattere confidenziale e sono a uso esclusivo del >>>>> destinatario. Nel caso >>>>> >>>>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>>>> che la sua diffusione >>>>> >>>>> e riproduzione è contraria alla legge e prego di darmi >>>>> prontamente avviso >>>>> >>>>> e di cancellare quanto ricevuto. Grazie. >>>>> >>>>> * >>>>> * 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/ >>>> >>>> * >>>> * 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/ >>> >>> >>> >>> -- >>> Rispetta l'ambiente: se non ti è necessario, non stampare questa mail >>> >>> >>> >>> Le informazioni contenute in questa comunicazione e gli >>> eventuali documenti allegati >>> >>> hanno carattere confidenziale e sono a uso esclusivo del >>> destinatario. Nel caso >>> >>> questa comunicazione Vi sia pervenuta per errore, Vi informo >>> che la sua diffusione >>> >>> e riproduzione è contraria alla legge e prego di darmi >>> prontamente avviso >>> >>> e di cancellare quanto ricevuto. Grazie. >>> >>> * >>> * 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/ >> >> * >> * 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/ > > > > -- > Rispetta l'ambiente: se non ti è necessario, non stampare questa mail > > > > Le informazioni contenute in questa comunicazione e gli > eventuali documenti allegati > > hanno carattere confidenziale e sono a uso esclusivo del > destinatario. Nel caso > > questa comunicazione Vi sia pervenuta per errore, Vi informo > che la sua diffusione > > e riproduzione è contraria alla legge e prego di darmi > prontamente avviso > > e di cancellare quanto ricevuto. Grazie. > > * > * 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/ * * 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/