The professionals use statistical packages and programs such as FactSet, to back-test ratios.

FORBES: The Quant Test

They are irrelevant because they are all dwarfed by another bias (for which there is no life-saving cure available in any of the statistical packages): publication bias.

FORBES: Publication Bias (or, Why You Can't Trust Any of the Research You Read)

Fortunately, the life of the researcher is made easy by standard statistical software packages.

FORBES: Publication Bias (or, Why You Can't Trust Any of the Research You Read)