 through e-mail or SMS - to complete questionnaires online (on desktop or mobile devices).</p>
<p>By inviting study participants several times a day to complete a questionnaire via the standard web browser of their mobile phone, active EMA an be implemented. This approach was taken in several large-scale studies, including ‘NESDA’ <span class="citation">(<a href="http://nesda.nl" class="uri">http://nesda.nl</a>; see also Chapter <a href="catalogue.html#catalogue">10</a>) and “HowNutsAreTheDutch” (<a