ng because it is possible to achieve the effect manually through an operation like <code>data$var &lt;- mean(data$var, na.rm = TRUE)</code> and passing the modified data frame to <code><a href="../reference/margins.html">margins(x, data = data)</a></code>.</p>
<p>At present, <code><a href="../reference/margins.html">margins()</a></code> does not implement the <code>over</code> option. The reason for this is also simple: R already makes data subsetting operations quite simple using simple <code>[</code> extr