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Re: st: taking the average of duplicate observations

From   Nick Cox <>
To   "" <>
Subject   Re: st: taking the average of duplicate observations
Date   Fri, 3 May 2013 12:01:37 +0100

Your reference to another post lacks a URL, nor can we comment on code
that you don't show us, but there is a one-word solution: -collapse-.

collapse rainfall, by(station year month)

But I've worked a lot with rainfall data, and I'm puzzled at what you
are doing here. If these are daily data, the convention is to use
totals, not means. -collapse- can do that too.


On 3 May 2013 11:48, Michael Tekle Palm <> wrote:
> Hello Statalist!
> I have observations with identical time values but different outcome values. Instead of dropping all but the first observations for every two/three duplicates, I want to calculate and replace with the average of the observations, and then drop the duplicates.
> So my data is on rainfall for a given location and is disaggregated by year and month. E.g:
> Station  |  Year  |  Month  |  Rainfall
> ---------------------------------------
>     1       1980       1          5
>     1       1980       1          3
>     1       1980       2          4
>     1       1980       3          8
>     1       1980       3          1
> So for each duplicate by station year month, I would like to calculate the average value for the rainfall outcomes, use this value and drop all duplicates. I think the solution suggested in this ["RE: st: questions about duplicate observations"] Statalist reply may work, but I wasn't quite able to make it work.

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