Included study	Design	Patient selection	Well-defined outcome	Protection Against Confounding	Protection against bias	Adequate power	Proper variables	Proper statistical methods	Reported included and excluded subjects	Global assessment	Global assessment: emergency department vs. non-emergency department infection rate
Dipietrantonio 1986 [27]	Retrospective chart review	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	High risk of bias	High risk of bias
Ferguson 1988 [28]	Retrospective chart review	Poor quality	Good quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Not done	High risk of bias	N/A
Chiang 2000 [25]	Retrospective chart review	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Not done	High risk of bias	N/A
Citak 2002 [26]	Prospective observational cohort	Unclear	Good quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	High risk of bias	High risk of bias
Nagashima 2006 [31]	Retrospective chart review	Good quality	Poor quality	Poor quality	Poor quality	Unclear	Poor quality	Poor quality	Poor quality	Moderate risk of bias	Moderate risk of bias
Trick 2006 [32]	Prospective observational cohort	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	Poor quality	High risk of bias	High risk of bias
Guzzo 2007 [34] and Xiao 2006 [35]	Prospective observational cohort	Unclear	Good quality	Good quality	Poor quality	Good quality	Good quality	Poor quality	Not done	Moderate risk of bias	N/A
Yilmaz 2007 [33]	Prospective observational cohort	Unclear	Good quality	Good quality	Poor quality	Poor quality	Poor quality	Good quality	Not done	High risk of bias	High risk of bias
Koh 2008 [30] and Gowardman 2008 [29]	Prospective observational cohort	Poor quality	Good quality	Poor quality	Poor quality	Poor quality	Good quality	Good quality	Good quality	Moderate risk of bias	High risk of bias