"If siblings are dissimilar, say, one is tall and one is short (relative to age and sex norms), the product will become negative (2 * -2 = -4)."
But what if one is super tall and one is average? (4 * 0 = 0)? And yet the actual difference between siblings is just as large as in your example. I don't get this method.
>(Why did they forget to remove one half-sibling on the left side?)
hehe
"If siblings are dissimilar, say, one is tall and one is short (relative to age and sex norms), the product will become negative (2 * -2 = -4)."
But what if one is super tall and one is average? (4 * 0 = 0)? And yet the actual difference between siblings is just as large as in your example. I don't get this method.
Yes, it's definitely unusual but apparently works in their simulations.