From historical data, the probability of a move greater than 5% to the downside after a confirmed Hindenburg Omen was 77%, and usually takes place within the next forty days. The probability of a panic sellout was 41% and the probability of a major stock market crash was 24%. Though the Omen does not have a 100% success rate, every NYSE crash since 1985 has been preceded by a Hindenburg Omen. Of the previous 25 confirmed signals only two (8%) have failed to predict at least mild (2.0% to 4.9%) declines.
Because of the specific and seemingly random nature of the Hindenburg Omen criteria, the phenomenon may be simply a case of overfitting. That is, by backtesting through a large data set with many different variables, correlations can be found that don't really have predictive significance. The Omen is at best an imperfect technical indicator that is a work in progress.