Asking questions about heritability


I would like to ask one simiple question but seems confusing me a little bit about heritability. Why is heritability is H2 but not H? I have tried to search for answers from Internet, but there seems to be no quick answers about it.



Hi Xueying

Good question. How things get named is often odd. After all, why is variance represented with s2? (I couldn’t figure out how to superscript the 2 on the forum).
Heritability is a proportion of the variance. Since the variance is a squared metric, so too is heritability, hence h2.

Thank you very much, Katrina. I understand.