### calculate log risk ratios and corresponding sampling variances</span></span></span>
<span class="r-in"><span><span class="va">dat</span> <span class="op">&lt;-</span> <span class="fu"><a href="escalc.html">escalc</a></span><span class="op">(</span>measure<span class="op">=</span><span class="st">"RR"</span>, ai<span class="op">=</span><span class="va">tpos</span>, bi<span class="op">=</span><span class="va">tneg</span>, ci<span class="op">=</span><span class="va">cpos</span>, di<span class="op">=</span>