|Materials and response rates|
|Hospitals||Voluntary participation§||Stratified sampling & Voluntary participation||Voluntary participation§|
|Respondents in the hospital||All healthcare workers||A part of the healthcare workers†||All healthcare workers or a part of the healthcare workers††|
|Period of survey||Jan 2009–Jan 2010||Jul 2007–Aug 2008||Jan 2006–Jun 2009|
|Number of participated hospitals|
|Number of the subjects|
|Recovery||8,192 (78.3%)||10,289 (88.0%)||337,862 (40.8%)|
|Valid data‡||6,963 (66.5%)||10,019 (85.7%)||291,341 (35.2%)|
§Hospitals were not selected randomly and participation was voluntary.
¶Ten hospitals participated voluntarily and 64 were selected randomly.
†Depending on the number of beds in each hospital, 10–300 questionnaires were distributed.
††The questionnaires were distributed to all staff at 637 hospitals and to some staff at 247 hospitals.
‡Incomplete questionnaires were excluded from the analysis, and included surveys with less than an entire section completed, surveys with fewer than half of the total items completed, or surveys with identical responses to every item.
Fujita et al.
Fujita et al. BMC Health Services Research 2013 13:20 doi:10.1186/1472-6963-13-20