Re: st: converting series of dates to numeric variable

[Nick Cox <njcoxstata@gmail.com>]

Yes, it should be mildly alarming, as it shows that you are trying
something which is inappropriate for you. But you can fix that.

The -date()- function converts to daily dates. That is its job. In
terms of daily dates, the resolution of your data (delta) is one day
and you have (lots of) gaps. Stata doesn't look out for equally spaced
dates in what it sees as gappy time series.

In your case I would recommend working with -floor(edate1/28)- as a
time variable, which gives equally spaced dates with 28 days as an
interval. Using -int()- or -ceil()- instead of -floor()- would work as
well. For example,

. di floor(date("1 Nov 2009", "DMY")/28)
650

. di floor(date("29 Nov 2009", "DMY")/28)
651

So go

gen edate2 = floor(edate1/28)
tsset identif2 edate2

Nick

On Wed, May 23, 2012 at 10:07 AM, loggyedr salvez
<loggyedy@googlemail.com> wrote:

> I have observations every 4 weeks (4-week period data).
>
> In  the excel.csv file i format the cells for the date column as follows
>
>           dates11                     identier            variable
>  November 1, 2009                  1
> November 29, 2009                  1
> December 27, 2009                  1
> January 31, 2010                     1
>  November 1, 2009                   2
>  November 29, 2009                  2
>   December 27, 2009                2
>   January 31, 2010                   2
>
> and then I use the commads:
>
> gen edate1 = date(dates11, "MDY")
> format edate1  %d
>  tsset identifier edate1
>
>
>
> and I get the following stata message:
>
> tsset identif2 edate1
>       panel variable:  identif2 (strongly balanced)
>        time variable:  edate1, 02nov2008 to 09oct2011, but with gaps
>                delta:  1 day
>
>
> Is this message something alarming? why "gaps"? and why delta "1 day"

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