(\widehat{\mbox{var}}^{+}\)</span> will overestimate variance, leading to an
overestimate of autocorrelation and an underestimate effective sample
size.</p>
<p>Because of the noise in the correlation estimates <span class="math inline">\(\hat{\rho}_t\)</span> as
<span class="math inline">\(t\)</span> increases, a typical truncated sum of <span class="math inline">\(\hat{\rho}_t\)</span> is used.
Negative autocorrelations may occur only on odd lags and by summing
over pairs starting from lag 0, the paired au