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Re: st: Converting MM, YY varkables into a date variable

From   Nick Cox <>
Subject   Re: st: Converting MM, YY varkables into a date variable
Date   Tue, 1 Feb 2011 22:55:50 +0000

I didn't see this before making my own suggestions.

Daily date variables are not at all needed if the data are monthly. In
fact they have the marked disadvantage that after -tsset- it appears
that roughly 29/30 of the data should be present but have been

But should you wish to produce daily variables for monthly data, as
Michael is assuming, then you don't need to create a variable holding
a constant. as -mdy(MM, 1, YY)- is perfectly legal. On the very odd
occasions I have done this, as when some data are daily and others
monthly, I have typically used -mdy(MM, 15, YY)- as better for
graphical purposes.


On Tue, Feb 1, 2011 at 10:44 PM, Michael McCulloch
<> >
You can assume "day" is any day of the month, for example the 1st day.
> *to make your variable, which we can call edate,
>        gen DD=1
>        gen edate = mdy(MM, DD, YY)
> *to confirm accuracy, compare visually:
>        list MM DD YY edate
> On Feb 1, 2011, at 2:37 PM, Jung-eun Lee wrote:
>> I need help with converting month and year variables into a date variable so that I can use it for a time-series analysis.
>> Year variable: YY (looks like 1992, 1993, 1994...)
>> Month variable: MM (looks like 1, 2, 3, 4...)

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