STOCK traders hang on central bankers’ every utterance. They scan news sites for market-moving events, such as terrorist attacks, and monitor President Donald Trump’s tweets for hostility towards publicly traded firms. Curiously, though, few analyse goings-on in Congress, which can shift the course of the world’s largest economy. Jonathan Strong, a former reporter (including at Roll Call, a sister publication of The Economist), hopes to change that.

With the help of 0ptimus, a firm of Republican data wonks, he has spent three years building Legis, an algorithm powered by vast quantities of data and a neural network (a computer system modelled on the human brain), which predicts the outcome of congressional votes. Each of the 44 votes it has forecast so far has been correct. Last year a hedge fund (which does not want to be named) began trading derivatives using its predictions.

According to legend, carrier pigeons brought news of the Duke of Wellington’s…Continue reading