Efficient score
= Efficient score
{title2=$\widetilde\ell=\dot\ell-\Pi_{\mathcal N}\dot\ell$}
The efficient score is the residual after <orthogonal projection> of the parametric <score function> onto the <nuisance tangent space>. It is centered and orthogonal to every nuisance direction. Its squared <L2 norm> is the <efficient information>.