Re: st: FW: How to make 'contract' create a row of zerofrequencies?

[Roger Harbord <roger.harbord@bristol.ac.uk>]

One solution could be to use -tabcount- by Nick Cox, available from SSC. 
You specify a list of values which define the categories of a variable that 
are to be counted, and zero frequencies are then included. The -replace- 
option makes it function much like -contract-, except zero frequencies are 
retained for the specified values.

Roger.


--On 22 May 2006 11:52 +0100 Pauline Rogers <Pauline.Rogers@cancer.org.uk> 
wrote:


> Dear All,
>
> I have a large dataset containing information on individuals attending for
> screening at several centres.
>
> I am writing a program to summarise monthly attendance, to be run
> regularly by one of our administrators.  So I first 'contract' my data to
> create a new dataset of the number of attendances for each centre for
> each month.  I used the following statement:
>
> contract centre3 mrec, freq(count) zero
>
> (Centre3 = centre code, mrec = month code)
>
> I have discovered that when there are no attendances in a month at any of
> the centres, Stata completely excludes this month rather than create a
> zero count for each centre.
>
> This then completely throws out my summary statistics.  Is there any way I
> can force 'contract' to create a count of zero for each centre for any
> month with zero attendance at all centres?
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