ar that the function is used to select individual PHQ-9 items. Comment your code. You will do yourself and your colleagues a big favor by making it much easier to quickly grasp the meaning of your code.</p>
</div>
<div id="pre-process" class="section level2">
<h2><span class="header-section-number">4.6</span> Pre-process</h2>
<p>Once data are cleaned, you can enrich the data sets with variables that can be derived from the raw data, such as, e.g., survey sum-scores, or actigraphy summary measures (see Chapt