[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

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

Subject |
RE: st: A rose by any other name? |

Date |
Fri, 14 Nov 2008 12:37:54 -0000 |

The references given in my reference give many further details. (Seemingly, no one actually read it.) I read somewhere that the logistic is just a special case of a Riccati equation, which would make its implicit discovery an 18th century matter. I never followed that up; I do note that several quite different things have been called Riccati equations. But implicit discovery aside, it's my understanding that Verhulst easily deserves as much credit as anyone. Nick n.j.cox@durham.ac.uk Lachenbruch, Peter Wikipedia gives Verhulst as the originator of the logistic curve, but I recall that Adolphe Quetelet had also done some work in this area. Both were contemporaries (early 1800s) - Verhulst lived from about 1804 to 1849 and Quetelet from about 1809 to 1874 - I'm not sure about these dates even though I just looked them up on Wikipedia (laziness to not go back). Interestingly, there is no mention of the logistic curve in the Quetelet article. Can anyone expand on my impression? BTW, Quetelet is credited with developing the Body Mass Index, BMI jverkuilen I believe you are right about the logistic curve predating the distribution From what I recall it was first derived (using a firstorder nonlinear differential equation) by Verhulst to model population as an elaboration of Malthus' model, which is verbal but corresponds to the first order linear differential equation for exponential growth. Been a while since I read any of that stuff so my memory may be faulty. Verhulst's equation is a popular example for a nonlinear ODE that can be solved analytically. There are so few... Nick Cox As a matter of history, I believe that logistic as a growth curve came long before the logistic as a CDF, but as Jay implies, between friends it's the same equation. There are some historical references on this within SJ-8-1 gr0032 . . . . . . . Stata tip 59: Plotting on any transformed scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox Q1/08 SJ 8(1):142--145 (no commands) tip on how to graph data on a transformed scale Verkuilen, Jay >>To be more precise, the proposed model is a gamma density kernel, not a bonafide gamma density ,which integrates on 1. Of course in this context, the function is used to model nonlinear trend, not a probability distribution of some random variable.>> Right, and thus it's not dissimilar from using the logistic CDF as a model for growth between asymptotes, which is often done using, say, Gaussian errors around the curve itself. * * 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/

**References**:**RE: st: A rose by any other name?***From:*jverkuilen <jverkuilen@gc.cuny.edu>

**RE: st: A rose by any other name?***From:*"Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>

- Prev by Date:
**RE: st: RE: if and if** - Next by Date:
**st: 2009 MEXICAN STATA USERS GROUP MEETING: First Announcement and Call for Presentations** - Previous by thread:
**Re: st: resend** - Next by thread:
**st: Re: Memory** - Index(es):

© Copyright 1996–2017 StataCorp LLC | Terms of use | Privacy | Contact us | What's new | Site index |