# Can the value of heritability be greater than 1?

Heritability defined as genetic variance divided by total variance seems to be bounded between 0 and 1. However, I see a way of calculating heritability on this page (http://www.radford.edu/~rsheehy/Gen_flash/Tutorials/Linear_Regression/reg-tut.htm) with: 2*Covxy / Varx. However, a result calculated in this way could be greater than 1. What am I missing?

• I am missing where on that site it is stated the formula you are giving is calculating heritability. – skymningen May 15 '17 at 13:08
• Where it says "Calculating the slope," but I multiply by 2 for a sexual population, according to the last paragraph on the page. – sterid May 15 '17 at 13:19
• @skymningen It's at the bottom: "Regression of offspring on only one parent underestimates narrow-sense heritability by about 50%. Therefore, Christine's analysis suggested a narrow-sense heritability of 2 x 0.414 = 0.828." The problem is that if you had both parents, the slope would be closer to 0.828, and it wouldn't be doubled. – kmm May 15 '17 at 13:23