In the original edition of 'What works on Wall Street', O'Shaughnessy wrote that the single-best value factor was a company's price-to-sales ratio (P/S). In his latest edition, the P/S continues to perform well. Still, it was unseated by the value composites and EBITDA/EV due to 2 reasons: (1) A broader scope of analysis by using deciles and (2) two very bad years for P/S, e.g. 2007 and 2008.

A stock's P/S is similar to its P/E ratio, but it measures the company's price against its annual sales instead of earnings.

It's calculated as follows:

In the scorecard, we show the P/S for the selected stock. We also calculate the median P/S for all stocks, the company's sector, industry group, and industry. Finally, we include the percentile to compare a company to its peers easily. For more information, click here.