[extropy-chat] Inside Vs. Outside Forecasts

[Robin Hanson]

At 08:23 PM 10/11/2005, Eliezer S. Yudkowsky wrote:
>>>>The application to our forecasts about the future should be 
>>>>obvious: Do we overestimate technical change because we tend to 
>>>>take an inside view, imagining the particular process that 
>>>>produces some innovation, instead of an outside view, looking at 
>>>>how long similar innovations have taken in the past?
>>>
>>>I am inclined to think that this is not the reason.  I may not 
>>>fully understand this distinction, but it sounds like the "inside 
>>>view" is based on analysis from a position of some expertise and 
>>>detailed knowledge of the problem domain.  Scenarios and
>>>extrapolations are constructed based on this detailed knowledge.
>>That is not how I read the distinction.  It seems to me more about 
>>imagining a story about the process.  So people basing their 
>>forecasts on science fiction novels would count as an inside 
>>view.  But I won't know for sure until I can read the paper.
>
>I've read the paper and this is correct.  The inside view is based 
>on telling stories about the process.  The outside view is based on 
>stupidly using the mere statistical base rate, without any attempt 
>whatsoever to "adjust" for the "special features" of the case.

I've now also read the paper and I agree.  The paper says:

>An inside view forecast is generated by focusing on the case at 
>hand, by considering the plan and the obstacles to its completion, 
>by constructing scenarios of future progress, and by extrapolating 
>current trends. The outside view ... ignores the details of the case 
>at hand, and involves no attempt at detailed forecasting of the 
>future history of the project. Instead, it focuses on the statistics 
>of a class of cases chosen to be similar in relevant respects to the 
>present one. ... An inside view forecast draws on knowledge of the 
>specifics of the case, the details of the plan that exists, some 
>ideas about likely obstacles and how they might be overcome. In an 
>extreme form, the inside view involves an attempt to sketch a 
>representative scenario that captures the essential elements of the 
>history of the future. In contrast, the outside view is essentially 
>statistical and comparative, and involves no attempt to divine 
>future history at any level of detail.

It still seems to me that this group tends to base its forecasts a 
bit too much on constructing scenarios, and a bit too little on 
statistics about similar past situations.





Robin Hanson  rhanson at gmu.edu  http://hanson.gmu.edu
Associate Professor of Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030-4444
703-993-2326  FAX: 703-993-2323