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From |
Lars Folkestad <lfolkestad@health.sdu.dk> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: age: factor variables may not contain noninteger values |

Date |
Tue, 8 Nov 2011 20:47:37 +0100 |

Thats true but biologically when i'm 39years and 10 months i'm closer to 40 than 39. Im not sure it makes a difference but it might - floor may potentially underestimate the effect of age. lars Den 08/11/11 20.39 skrev "Nick Cox" <njcoxstata@gmail.com>: >All that said, as age as an integer usually means "age last birthday", >I am surprised that -round()- is regarded as the answer. I would put >my foot down for -floor()-. > >For example, I am 19 and will not be 20 until next birthday. > >Nick > >On Tue, Nov 8, 2011 at 7:29 PM, Lars Folkestad <lfolkestad@health.sdu.dk> >wrote: >> 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 >>>Folkestad >>>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 >>>>-------------------------- >>>> >>>>* >>>>* For searches and help try: >>>>* http://www.stata.com/help.cgi?search >>>>* http://www.stata.com/support/statalist/faq >>>>* http://www.ats.ucla.edu/stat/stata/ >>> >>> >>>* >>>* For searches and help try: >>>* http://www.stata.com/help.cgi?search >>>* http://www.stata.com/support/statalist/faq >>>* http://www.ats.ucla.edu/stat/stata/ >>> >>>* >>>* For searches and help try: >>>* http://www.stata.com/help.cgi?search >>>* http://www.stata.com/support/statalist/faq >>>* http://www.ats.ucla.edu/stat/stata/ >> >> >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/statalist/faq >> * http://www.ats.ucla.edu/stat/stata/ >> > >* >* For searches and help try: >* http://www.stata.com/help.cgi?search >* http://www.stata.com/support/statalist/faq >* http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: age: factor variables may not contain noninteger values***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**Re: st: age: factor variables may not contain noninteger values***From:*Nick Cox <njcoxstata@gmail.com>

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