Judging from the literature, in particular the wide range of popular finance books, the possibility of predicting future movements in financial markets ranges from significant (see, for example, the many books on chartism) to impossible (see, for example, [14]). Another scenario of course does exist that financial markets may neither be predictable or unpredictable all the time, but may instead have periods where they are predictable (i.e. non-random) and periods where they are not (i.e. random). Evidence for such ‘pockets of predictability’ were found several years ago, by Johnson et al. [10]. A similar study was reported subsequently by Sornette et al. [2]. However, a formal report of a theoretical framework for identifying such periods of predictability has not appeared in the literature to date.
The rationale behind our initial proposal to predict financial markets using artificial market models, is as follows. Financial markets produce time-series, as does any dynamical system which is evolving in time, such as the ambient air-temperature, or the electrical signals generated by heart rhythms. In principle, one could use any time-series analysis technique to build up a picture of these statistical fluctuations and variations - and then use this technique to attempt some form of prediction, either on the long or short time-scale. One example would be to use a multivariate analysis of the prices themselves in order to build up an estimate of the parameters in the multivariate expansion, and then run this model forwards. However, such a multivariate model may not bear a relation to any physical representation of the market itself. Instead, imagine that we are able to identify an artificial market model which seems to produce the aggregate statistical behavior (i.e. the stylized facts) observed in the financial market itself. It now has the additional advantage that it also mimics the microscopic structure of the market, i.e. it contains populations of artificial traders who use strategies in order to make decisions based on available information, and will adapt their behavior according to past successes or failures. All other things being equal, we believe that such a model may be intrinsically ‘better’ than a purely numerical multivariate one - and may even be preferable to many more sophisticated models such as certain neural network approaches, which also may not be correctly capturing a realistic representation of the microscopic details of a physical market. The question then arises as to whether such an artificial market model could be ‘trained’ on the real market in order to produce reliable forecasts.