With this combination we took the lowest 20% of price-to-sales ratio companies and combined them with the second factors we tested for.
Even though price-to-sales is also a valuation factor, on average, using this combination gave the lowest returns of all the two-factor strategies we tested, generating an average return of 345.3% (median 333.4%). The best performing strategy was selecting companies with a cheap price-to-sales ratio as well as companies with the highest 6-months price index values. This would have given you returns of 563% over 12 years.
The worst combination would have been combining the low price-to-sales ratio companies with those that generated the highest ROIC over the past five years. Using this strategy your return would have been 184.8%.