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From |
Nils Braakmann <nilsbraakmann@googlemail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Including constant? |

Date |
Thu, 2 Jun 2011 06:31:44 +0100 |

Interesting to learn about these disciplinary differences. In economics the most common thing nowadays seems to be to only report coefficients/results for your main variable of interest, omit results for control variables, constants etc. and just mention that these were included somewhere in the text/a table footnote. Cheers, Nils On Wed, Jun 1, 2011 at 5:28 PM, Nick Cox <n.j.cox@durham.ac.uk> wrote: > In various Earth and environmental sciences in which I write or review papers leaving out the constant would be generally regarded as gross statistical illiteracy. > > Nick > n.j.cox@durham.ac.uk > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Williams > > At 07:23 AM 6/1/2011, lreine ycenna wrote: >>Do we typically not have to include constants in regression tables >>when presenting them? > > You can probably say most or all of what you want to say without > including the constant. After all, how many times do you see a paper > discussing the values of the constants? > > But, I personally always include them. It is particularly useful if > somebody wants to calculate a yhat value for some combination of > values for the Xs. How useful the constant is as a standalone value > depends on the coding of the Xs. The constant is the value someone > would have if they had a value of 0 for every X. Often such a person > cannot exist because one or more variables cannot take on a value of > 0, e.g. nobody has 0 height, and nobody gets a score of 0 on a test > scaled to range between 400 and 1600. However, if you center the Xs > (subtract the mean from each case for each X) then the constant > becomes the predicted score for a person who has average values on > every X. Such a person (or someone close to it) may actually exist, > making the constant more interpretable as a stand-alone number, i.e. > the constant is the score a totally average person would be expected > to have. Or, if the model just has dummy variables (female, black) > then the constant could be the average score for, say, a male white. > > > * > * 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: Including constant?***From:*Richard Williams <richardwilliams.ndu@gmail.com>

**References**:**st: Including constant?***From:*lreine ycenna <lreine.ycenna@gmail.com>

**Re: st: Including constant?***From:*Richard Williams <richardwilliams.ndu@gmail.com>

**RE: st: Including constant?***From:*Nick Cox <n.j.cox@durham.ac.uk>

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