rror are used, which will always have positive expectations for an imperfect estimator. <em>Absolute error</em> is defined as <span class="math display">\[
\textrm{abs-err} = \left| \hat{\theta} - \theta \right|
\]</span> and <em>squared error</em> as <span class="math display">\[
\textrm{sq-err} = \left( \hat{\theta} - \theta \right)^2.
\]</span> <span class="citation" data-cites="GneitingRaftery:2007">Gneiting and Raftery (<a href="#ref-GneitingRaftery:2007" role="doc-biblioref">2007</a>)</span> provide a