It can determine innate ability which isn't affected by environmental factors. From there we can determine a how much individuals are affected by those factors.

It can determine innate ability which isn't affected by environmental factors. From there we can determine a how much individuals are affected by those factors. For example, Billy and Joey were determined to have the same innate ability. Joey scored 20 points less than Billy on the standardized test. Joey also lives next to a power plant and has lead pipes in his house.