All regions of Latvia were represented in the pool of returned questionnaires with most of them (101) coming from capital city Riga.
From this pool of potential participants, questionnaires were sent to a random sample of 978 people with 505 questionnaires returned (response rate 51.6 %).
In addition to public database searches we added a thorough hand search of reference sections and the PROQOLID database, resulting in an extensive domain and item pool of physical activity questionnaires.
Using a systematic approach, an initial pool of items for the questionnaire was developed and refined on the basis of rigorous content and face validity assessments and factor analysis.
Therefore, we developed a pool of 37 Likert-type survey questionnaire items to describe medical educators' views of psychiatry and psychiatrists.
A pool of items identified from existing questionnaires during concept identification was used as a reference to inform item construction.
The sample frame for the current study was drawn from the pool of individuals who returned completed questionnaires from the phase 1 of the KCMHR military health study and who gave signed consent to be followed up.
Schools being physically visited were selected out of the pool of those schools who completed the questionnaire.
The distribution of questionnaire files and links to the online Google form started at the end of August 2011 and pooling of answers was started in mid-November 2011.
A pool of 110 potential items formed the first questionnaire version.
