We show that Mallows' model averaging estimator proposed by Hansen (2007) can be written as a least squares estimation with a weighted L₁ penalty and additional constraints. By exploiting this representation, we demonstrate that the weight vector obtained by this model averaging procedure has a...

Parents preferring sons tend to go on to have more children until one or more boys are born, and to concentrate investment in boys for a given sibsize. Therefore, having a brother may affect child outcomes in two ways: indirectly, by decreasing sibsize, and directly, where sibsize remains...