> <span class="op">&lt;-</span> <span class="va">dat.konstantopoulos2011</span></span>
<span></span>
<span><span class="fu"><a href="https://rdrr.io/r/utils/head.html" class="external-link">head</a></span><span class="op">(</span><span class="va">dat</span><span class="op">)</span></span>
<span><span class="co">#&gt;   district school study year    yi    vi</span></span>
<span><span class="co">#&gt; 1       11      1     1 1976 -0.18 0.118</span></span>
<span><span class="co">#&gt; 2       11      2     2 1