suppose you dataset is
id country temp hum
1 1 24 45
2 2 26 55
3 2 26 55
4 3 29 65
etc.
One solution might be then:
. // Store the Properties of the Alternatives
. preserve
. by country, sort: keep if _n==1
. ren country alt
. keep alt temp hum
. tempfile cov
. sort alt
. save `cov'
. // Construct Choice-Sets
. restore
. keep id country
. expand 3
. by id, sort: gen alt = _n
. gen choice = alt == country
. // Merge Properties of the Alternatives back-in
. sort alt
. merge alt using `cov'
many regards
uli
PS: Personaly, I would add the quality of restaurants to the theoretical
model, with values France 100, Spain 99, and Germany 4.23 ;-)
Stata User wrote:
> I have observations of 4 holiday passengers choosing between going on
> holiday
> in 3 different countries: Germany, France and Spain. So country is the
> categorical
> choice variable. This categorical choice variable has 2 attributes:
> temperature and
> humidity. This is how the data structure looks like now (simplified
> example)
>
>
>
> Table 1:Data Structure Now
>
> | Choice (country) | Temperature | Humidity | |
>
> Passenger 1 | Germany | 24 | 45 |
> Passenger 2 | France | 26 | 55 |
> Passenger 3 | France | 26 | 55 |
> Passenger 4 | Spain | 29 | 65 |
>
>
> Now I want to replace the categorical choice variable 'country' with a
> dichotomous
> choice variable. This means when a passenger chooses Germany and he does
> not choose France and Germany, we observe three decisons of the passenger
> which will be coded with '1' for Germany and '0' for France and Spain. So
> this below in
> Table 2 is the data structure I desire. Since I have too much data, I have
> to find a
> programming solution in order to transform Table 1 into Table 2.
>
>
> Table 2: Desired Data Structure via Programming
>
> | Dichotomous | Categorical choice | Temperature |
>
> Humidity |
>
> | choice variable | variable |
>
> Observation 1 | 1 | Germany | 24 | 45 |
> Observation 2 | 0 | France | 26 | 55 |
> Observation 3 | 0 | Spain | 29 | 65 |
> Observation 4 | 0 | Germany | 24 | 45 |
> Observation 5 | 1 | France | 26 | 55 |
> Observation 6 | 0 | Spain | 29 | 65 |
> Observation 7 | 0 | Germany | 24 | 45 |
> Observation 8 | 1 | France | 26 | 55 |
> Observation 9 | 0 | Spain | 29 | 65 |
> Observation 10| 0 | Germany | 24 | 45 |
> Observation 11| 0 | France | 26 | 55 |
> Observation 12| 1 | Spain | 29 | 65 |
>
>
> Thank you for your help,
>
> Stata User 2005 from Europe
>
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