It is difficult to comment on Stata's behaviour
here as you do not give information on precisely
what commands you used.
In general, if you type
sort husband
any solution in which -husband- is in the
correct order is possible. If you type
sort husband wife
then the solution will be constrained
by the order of -wife-. It is also possible
that
sort husband, stable
will be useful for your purposes. It is not
clear which part of this you already know.
Nick
[email protected]
D.C.J. Vissers
> I have a dataset of nearly 3000 couples. One record consists
> of data of
> both the man and the woman. There are some polygamous marriages, so 1
> man can have 2 or 3 women instead of 1 woman. In this case,
> there are 2
> or 3 records with the same data for the man and different data for the
> women.
> For my analyses of men, I only want 1 record of polygamous men.
> Therefore, I create duplicates based on idnumbers. Before this
> duplication I sorted the data on idnumbers and 1 variable of the men,
> namely mobility status. This status is the same for 1 man
> with different
> wives.However, the data of the corresponding wifes will be
> different. I
> noticed that Stata randomly selects the order of the
> different wives in
> polygamous men. See also the following example:
>
> Attempt 1:
> data of man 1 - wife 1
> data of man 1 - wife 2
> data of man 1 - wife 3
>
> Attempt 2:
> data of man 1 - wife 3
> data of man 1 - wife 1
> data of man 1 - wife 2
>
> I kept the first record of every duplicate. This means that
> in attempt 1
> Stata kept wife 1, and in attempt 2 wife 3. This might not give big
> problems, but after this I make another selection. I also need to know
> the mobility status of women. Suppose, this status is known
> for wife 1 &
> 2, but not known (missing) for wife 3. This means that I will find
> different numbers in attempt 2. And that is also what
> happened. I found
> small differences in different attempts (number of records:
> 1519 vs 1517
> vs 1512).
>
> My questions:
> 1. Why does Stata randomly order records after a certain sorting?
> 2. How can I make sure that every time the same selection is made?
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