A new study from the University of Iowa shows evidence that stock price movements are, in fact, predictable during short windows.
The study by researchers in the Tippie College of Business suggests that price movements can be predicted with a better than 50-50 accuracy for anywhere up to one minute after the stock leaves the confines of its bid-ask spread. Probabilities continue to be significant until about five minutes after it leaves the spread. By 30 minutes, the predictability window has closed.