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Re: st: example about choice experiment datasheet


From   elisabetta capobianco <elisabetta.capobianco@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: example about choice experiment datasheet
Date   Mon, 26 Nov 2012 11:43:51 +0100

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/



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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/


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