Location score
= Location score
{title2=$\rho(e)=-f'(e)/f(e)$}
The location score is the <score function> for translating a <probability density function> $f$. The minus sign comes from differentiating $f(y-\theta)$ in $\theta$. Under regular tail conditions, <integration by parts> gives $E_f\rho=0$ and $E_f(\varepsilon\rho)=1$. These identities determine projections of the <score function> onto the span of the centered error.