Another university in this category, Lampeter, failed to return the questionnaire on time, which meant that its replies to questions on environmental policy and staff did not appear.
Of the 30 included patients, 3 girls were dropped out of the study because of consuming analgesics or failure to answer the phone and fill the questionnaire on time.
A total of 126 rheumatologists (including rheumatologists in training) (50%), 132 clinical nurse specialists (56%), and 112 physical therapists (53%) returned the questionnaire on time (Table 1).
Respondents who did not return the completed questionnaire on time received three reminders, in two-week interval, from either the researcher or from a staff member of the local health service.
Three types of lotteries were run: (i) daytrip tickets for the whole family to a popular amusement park if they returned all postal questionnaires, (ii) €12.50-worth gift vouchers for sending back the questionnaire on time after each questionnaire round and (iii) a combination of (i) and (ii).
At baseline, participants categorized their number of overnight hospitalizations according to the options on the questionnaire (none, one time, two times, more than two times).
In addition there were standard questionnaires on lost time (HALT index [10]), quality of life (WHOQoL-8 [11]) and anxiety and depression (HADS [12]).
In a previous study (Swan et al. 2003), we examined selection bias by comparing questionnaire data on time to pregnancy and history of infertility, as well as demographics, of study subjects and nonparticipants and of men who did and did not give semen samples.
The strong engagement from the administrative staff and research assistants undoubtedly helped in making sure the questionnaires were completed on time.
These files contain math and reading test scores as well as student responses to a brief questionnaire on their time use outside of school.
