Datacasting: What will you buy tomorrow?
By Jim Giles and Peter Aldhous We put a new breed of number-crunching forecasters to their toughest test yet – predicting sales of New Scientist See gallery: “Brains, delusion, mummies: Best New Scientist covers“ CROESUS, the king of ancient Lydia, wanted to know the future. It wasn’t going to be easy. First he had to climb the slopes of mount Parnassus to consult the Pythia, a Greek oracle. Those granted an audience received a prophecy, but only if they brought along a sacrificial goat. Having heard the prophecy, expressed in enigmatic verse, they then had to figure out what it meant. Croesus was told that a great empire would fall if he went to war. He invaded his Persian neighbours, only to discover that the ill-fated empire was his own. It might seem as if little has changed. Business leaders and politicians still turn to forecasters, who often charge high sums for their services. And yet their predictions can be unhelpful, if not wildly inaccurate. Many technology analysts said the iPad would be a flop; it has sold tens of millions. The movie Titanic was supposedly destined for a fate as miserable as the ship; it earned almost $2 billion. As the old joke goes, prediction is hard – especially about the future. Yet there is a buzz about the prediction business. That’s because forecasters have a new place to look for answers. This time, their efforts are based on data – mountains of data,