The unsolved problem of otitis media in indigenous populations: a systematic review of upper respiratory and middle ear microbiology in indigenous children with otitis media

Table 1 Risk of bias assessment

	Reference	Did the study address a clearly focused issue?	Cohort recruitment acceptable?	Exposure accurately measured?	Outcome accurately measured?	Important confounding factors identified?	Important confounding factors accounted for?	Are the results precise?	Are the results believable?	Do results fit with other available data?	Overall quality score
1972, Stuart*	[46]	+	+	–	–	+	–	–	–	–	Poor
1975, Copeman	[44]	–	–	–	–	–	–	?	–	–	Poor
1975, Stuart	[45]	+	+	–	–	–	–	–	–	–	Poor
1985, Dawson	[55]	+	–	+	+	–	–	?	–	–	Poor
1994, Leach	[20]	+	+	+	+	–	–	–	+	+	Mod
1996, Homøe	[34]	+	+	+	+	+	+	+	+	+	Good
1999, Parkinson	[38]	+	+	+	+	–	–	+	+	+	Mod
2003, Couzos*	[40]	+	?	+	+	+	+	+	+	+	Good
2003, Stuart	[49]	+	?	+	+	+	–	+	+	+	Mod
2005, Gibney	[50]	+	+	+	?	–	–	+	+	+	Poor
2006, Leach*	[51]	+	?	+	+	–	–	–	–	+	Poor
2007, Ashhurst-Smith	[37]	+	?	+	+	–	–	?	+	–	Mod
2008, Leach*	[43]	+	+	+	+	–	–	+	+	+	Mod
2008, Leach*	[54]	+	+	+	+	–	–	+	+	+	Poor
2009, Homøe*	[39]	+	+	+	+	–	–	–	–	–	Poor
2009, Mackenzie*	[52]	+	?	–	+	–	–	+	–	+	Poor
2010, Morris *	[53]	+	+	+	+	+	+	+	+	+	Good
2011, Binks	[35]	+	?	?	+	–	–	+	+	+	Poor
2012, Marsh	[56]	+	?	+	+	–	–	+	+	+	Mod
2012, Sun	[36]	+	+	+	+	+	+	+	+	+	Good
2013, Smith-Vaughan	[48]	+	+	+	+	–	–	+	+	+	Mod
2013, Stephen*	[42]	+	?	+	+	–	–	+	+	+	Mod
2015, Jervis-Bardy	[57]	+	?	+	+	+	+	+	+	+	Good
2015, Leach*	[47]	+	?	+	+	–	–	+	+	+	Mod
2016, Leach*	[16]	+	?	+	+	+	–	+	+	+	Mod

Data based on CASP-based risk of bias assessment. Assessment of bias pertained to the microbiology data and not to clinical data. ?, this variable was unable to be assessed
*Studies where microbiological outcomes were not the primary outcome

ISSN: 2049-2618