Late samples allow larger sample sizes for estimation of factors. While that may be part of the
reason for good results for late samples, that is not a sufficient condition for good results because our
robustness checks found that the when the British pound is the base currency, late samples perform worse
than early samples. Indeed, it remains to be seen whether our results for late samples are spurious. In any
event, the framework here can be extended in a number of ways. It would be desirable to allow different
slope coefficients across currencies, to allow more flexible specification of parameters in monetary and Taylor rule models, and to use a data dependent method of selecting the number of factors. Such
extensions are priorities for future work. It would also be desirable to compare our predictions to not only
a random walk model, but to other models that have been compared to the random walk in earlier studies