<p>The different stages of the survey ensure that the process meets the requirements for statistical production:</p>
<ul>
<li>stratified sampling</li>
<li>reminders and controls of data being collected</li>
<li>data cleaning</li>
<li>correction of overall non-response</li>
<li>calibration</li>
<li>correction of partial non-response</li>
<li>the questionnaire was tested in 2013 upstream of the collection, with 97 establishments.</li>
</ul>