The ability of futures markets to predict subsequent spot prices has been a controversial topic for a number of years. Empirical evidence to date is mixed; for any given market, some studies find evidence of efficiency, others of inefficiency. In part, these apparently conflicting findings reflect...

Monthly data on the $US/ECU exchange rate are analysed in light of the random walk hypothesis. A battery of tests, including procedures that are robust to conditional heteroscedasticity, are applied against linear alternatives to departures from the random walk. These tests are all based on the...

Much research has been devoted to assessing the evidence for linear trend in a time series. We discuss the statistical implications of some recent developments, with specific application to 24 time series of relative primary commodities prices. Copyright 2003 Blackwell Publishing Ltd.