From: John Conover <john@email.johncon.com>

Subject: Re: WWII: Causes and Effects.

Date: 5 Sep 1999 04:05:56 -0000

George Stebbins writes: > On Fri, 03 Sep 1999 05:50:15 GMT, conover@rahul.net wrote: > > >George Stebbins writes: > > >> > >> But there has been one change in the business cycle and that is the > >> and that is an increase the longevity of the expansions in the post > >> war period. And even Romer's data supports that. I think this is > >> supported by this paper at the KC Fed. > >> > > > >Hi George. Its a bit of a paradox, but: > > > > http://www.johncon.com/john/correspondence/990215192020.29398.html > > > >tends to indicate that the frequency distribution of the run lengths > >of the US GDP's contractions and expansions agree very well with the > >traditional random walk fractal model, ie., the frequency distribution > >is erf (1 / sqrt (t)), irregardless of scale, and the statistics seem > >stationary in both the third and fourth quarters of this century. > > > > What paradox? We are not looking at ether the frequency of the depth > of the recession, but their duration > . . . > > >I don't know what to make of it, since the traditional random walk > >fractal model is stochastic, ie., dominated by lottery. > > > >Maybe we can't exercise as much authority over the US GDP as we think > >we can. > > > > If the above is true perhaps we do. > Hi George. If the above is true, then the depth should be proportional to the sqrt (t), (a fractal kind of thing,) too. If I get time, I will put up a graph of it, and we will see. John BTW, a lot of studies of contractions and expansions in the GDP are kind of dependent on how contractions or expansions are defined. The program that made the graphs looks at the marginal increment, from one time unit to the next, and if it went up, it was the start of an expansion, and if it went down, it was the start of a contraction. The expansion, or contraction, continued until the GDP was equal to the value that initiated it. How many time units intervened in between, (ie., the contraction's or expansion's run length,) was assembled into a frequency histogram, and integrated to get the cumulative distribution, which was graphed. Although consistent with formal fractal methodologies, it might not be consistent with traditional economic definitions of contraction or expansion. FYI. -- John Conover, john@email.johncon.com, http://www.johncon.com/

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