Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!sun-barr!decwrl!shelby!portia!matheson From: matheson@portia.Stanford.EDU (David Matheson) Newsgroups: comp.society.futures Subject: Re: Technology Forecasting Summary: probability does help Keywords: probability, forecasting, trend Message-ID: <9560@portia.Stanford.EDU> Date: 26 Feb 90 16:35:17 GMT References: <1930@husc6.harvard.edu> <9002240412.AA14891@world.std.com> <1936@husc6.harvard.edu> Sender: David Matheson Reply-To: matheson@portia.Stanford.EDU (David Matheson) Organization: Stanford University Lines: 48 In article <1936@husc6.harvard.edu> weber@popvax.harvard.edu (Bob Weber) writes: >The problem with probability space is that if you grant the premise >that the future occurs because of some event sequence (rather than >because of some sent of trends (even thought the former reflect the >more likely than any other future. For example, if you have 40 events >in a sequence leading to some outcome, and each event is highly probable, >say .9 likely, then the probability of this particular future is >.9 to the 40th power, or .017. This tells us that the world is highly >contingent. One goal should be to give up the notion of one particular >likely outcome and think in terms of alternative event sequences and >alternative outcomes. > >Regards >Bob Although I wholly agree with Bob's event notions for thinking about the technology of the future, I would have to take issue with the notion that probability is not very helpful. When making decisions (i.e. committing $ now) in anticipation of the future state of technology, it is critically important to know which scenarios (or sequences of events) are more plausible than others. What I have typically done is to: 1. Construct event definitions to serve as the progress of technology 2. Select representative sequences to serve as possible futures. 3. Assess a probability distribution over future states, using the representatives as proxies. Using models to help people represent their information, current decision tree technology can reach around 2,000 such scenarios. 4. Although the probability of any particular scenario is small (as Bob points out), one does not need to know the future in order to make a decision today. Rather, the entire collection of future possibilities should be taken into account. I think my work has a somewhat different focus that typical technology forecasting. Some want to forecast technology for the sake of forecasting technology (a slight charactature). I always have a specific decision in mind. Thus my event definintions, modelling, and so are all constructed so as to make the correct decisino as clear as possible. David Matheson Stanford University -- ______________________________________________________________ David Matheson matheson@portia.stanford.edu 376 College #5, Palo Alto, CA 94306-1545 (415) 328-3515