Create a Stata monthly date using 
gen date = mofd(dofw(yw(year,weeks)))
Also, note that 
egen meanwhatever = mean(whatever), by(date) 
and similar commands will automatically 
adjust for number of weeks assigned to 
each month and missing values. 
Nick 
[email protected] 
Thomas Speidel
 
> I have a dataset containing yearly and weekly data starting 
> from week 1
> 1999 (i.e. week of Jan 1, 1999) to week 53.  This is repeated 
> from year
> 1999 to year 2004.  I am trying to convert this data to monthly data,
> containing the total no. of units for each month of each year.  The
> problem is all months (except some Februarys) contain a 
> little more than
> 4 weeks, and so computing the total for each month is not
> straight-forward. I guess any solution will have to include 
> some error,
> which is fine.
> 
> Any ideas? Thanks for any suggestions.
> 
> The following is a sample of my data:
> 
> year	weeks	units
> 1999	1	600
> 1999	2	597
> 1999	3	588
> 1999	4	562
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