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From |
House Wang <jwanghouse@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: conception confusion - "fixed effects" and time effect on data with time factor |

Date |
Fri, 21 Oct 2011 15:56:37 -0500 |

I think I have learned something from your response. "models are supposed to be useful, not true." This is the most important of the discussion. Thank you very much. For the model, I want to measure the maturity of an institution in manipulating rules, which are supposed to increase across years. Proximately, it is like a kid grow up. This is why I use year as a trend variable. On Fri, Oct 21, 2011 at 12:37 PM, Maarten Buis <maartenlbuis@gmail.com> wrote: > On Fri, Oct 21, 2011 at 6:58 PM, House Wang <jwanghouse@gmail.com> wrote: >> > > You are right to be skeptical, so am I. Your model identifies the > difference between "trend time" and "proxy time" using the assumption > that the trend is linear, which is almost never true. You really need > to decide what it is that you want to measure, and and think of a > model that will get you that. From that, derive the role time plays in > your model (note model, not data or reality or ...). By focusing on > what you want to know, you can often trim your model to manageable > proportions. If you try to represent "reality" your model tends to > explode. In the end: models are supposed to be useful, not true. > > 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/

**Follow-Ups**:**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Maarten Buis <maartenlbuis@gmail.com>

**References**:**st: conception confusion - "fixed effects" and time effect on data with time factor***From:*House Wang <jwanghouse@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Richard Williams <richardwilliams.ndu@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*House Wang <jwanghouse@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Maarten Buis <maartenlbuis@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*House Wang <jwanghouse@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Maarten Buis <maartenlbuis@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*House Wang <jwanghouse@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Maarten Buis <maartenlbuis@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*House Wang <jwanghouse@gmail.com>

**Re: st: conception confusion - "fixed effects" and time effect on data with time factor***From:*Maarten Buis <maartenlbuis@gmail.com>

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