Table 2

Risk of bias assessment for included studies

AuthorYearBias type
SelectionIdentificationClassificationConflict of
interest
Allan et al 11 1995HighLowLowLow
Flynn et al 12 2009HighLowLowLow
Flynn et al 17 2003HighLowLowLow
Flynn and Barker10 2006LowLowLowLow
Witte and Dundes19 2007LowHighUnclearHigh
Basco et al 15 2010HighHighUnclearLow
Flynn1999LowLowLowLow
LePorte et al 18 2009LowUnclearUnclearUnclear
Moniz et al 13 2011UnclearLowLowLow
  • Low: low risk of bias based on evaluation of study design and methods.

  • High: high risk of bias based on evaluation of study design and methods.

  • Unclear: insufficient data to evaluate risk.