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# Re: st: age: factor variables may not contain noninteger values

 From Lars Folkestad To "statalist@hsphsun2.harvard.edu" Subject Re: st: age: factor variables may not contain noninteger values Date Tue, 8 Nov 2011 20:29:31 +0100

```Thank you for that jesper. It sure did the trick.
lars

Den 08/11/11 13.17 skrev "Jesper Lindhardsen" <JESLIN01@geh.regionh.dk>:

>Hi Lars,
>
>Try
>
>
>g new_age= round(age_var,1)
>
>
>HTH,
>
>Jesper
>
>-----Original Message-----
>From: owner-statalist@hsphsun2.harvard.edu
>[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Lars
>Sent: 08 November 2011 12:14
>To: statalist@hsphsun2.harvard.edu
>Subject: Re: st: age: factor variables may not contain noninteger values
>
>This helps a lot.
>Thank you.
>
>But i have a question about the second point.
>Is there a quick and easy way to round the age to the nearest integer
>value? I could use the floor / ceil functions, but some of the ages
>Should be rounded up and some should be rounded down.
>
>lars
>
>Den 08/11/11 11.40 skrev "Maarten Buis" <maartenlbuis@gmail.com>:
>
>>On Tue, Nov 8, 2011 at 11:13 AM, Lars Folkestad wrote:
>>> I am trying to investigate the interactions between age and a
>grouping
>>>variable in a regression model, using this code:
>>>
>>> xi: regress Var1 age##i.group
>>>
>>> Var1: is a continuous variable
>>> Age: is a continous variable / float
>>>
>>> When i run the code i get the following error message:
>>> age:  factor variables may not contain noninteger values
>>
>>First, you are mixing -xi- and factor variable notation. You should
>>just leave the -xi:- prefix away.
>>
>>Second, in most surveys I am aware of age will be measured in whole
>>years. In those cases age should only contain integer values and this
>>error message means I made an error while preparing the data. This is
>>true regardless of how the data is stored. However, this is not
>>necessarily an error, you could have fractional age if you had for
>>instance exact birth dates and exact dates at which events of interest
>>happen. Alternatively, I may have standardized age or rescaled it so
>>it is measured in decades rather than years. However, in the latter
>>two cases I would have created new with different variable names
>>(probably z_age and age_d). So I would check whether non-integer age
>>would make sense given the way your data was collected.
>>
>>Third, whether there is an error or not you probably want -regress
>>var1 c.age##i.group- i.e. tread age as a continuous variable and not
>>as a set of dummies.
>>
>>Hope this helps,
>>Maarten
>>
>>--------------------------
>>Maarten L. Buis
>>Institut fuer Soziologie
>>Universitaet Tuebingen
>>Wilhelmstrasse 36
>>72074 Tuebingen
>>Germany
>>
>>
>>http://www.maartenbuis.nl
>>--------------------------
>>
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