ce/missingness will be evaluated.</p>
<p><code>ft_simple()</code> - identifies data fields where you only
want presence/missingness to be evaluated (but which are not necessarily
free text).</p>
<p><code>ft_strata()</code> - identifies a categorical data field which should
be used to stratify the rest of the data.</p>
<p><code>ft_ignore()</code> - identifies data fields which should be
ignored.  These will not be loaded.</p>
    </div>
    <div class="section level2">
    <h2 id="see-also">See also<a class=