Haldane prior
= Haldane prior
{c}
{title2=$\pi(p)\propto[p(1-p)]^{-1}$}
The Haldane prior has formal <beta distribution> parameters $(0,0)$. It is an <improper prior>, with infinite mass at both endpoints of $(0,1)$. For a <binomial distribution> likelihood with $s$ successes and $f$ failures, its posterior is $\operatorname{Beta}(s,f)$ only when $s,f>0$. A density flat in the log odds induces this kernel by the <Jacobian determinant> $d\log[p/(1-p)]/dp=1/[p(1-p)]$.