Study	Adequate sequence generation	Adequate concealment	Adequate blinding of participants and personnel	Adequate blinding of engagement outcome	Incomplete engagement outcome data addressed	Free of selective reporting	Free of other bias	Quality score
Elfeddali et al. 2012	Yes	Yes	Unclear	Yes	Unclear	Unclear	No	4/7
Danaher et al. 2012	Yes	Yes	Unclear	Yes	Unclear	Unclear	No	4/7
Houston et al. 2015	Yes	Yes	Yes	Yes	Unclear	Yes	No	6/7
Lieberman et al. 2006	Unclear	Unclear	Unclear	Yes	Unclear	Unclear	No	2/7
McClure et al. 2013	Yes	Yes	Yes	Yes	Yes	Unclear	No	5/7
Munoz et al. 2009	Yes	Yes	No	Yes	Yes	Unclear	No	4/7
Ramo et al. 2015	Unclear	Unclear	Unclear	Yes	Yes	Unclear	No	2/3
Schaub et al. 2015	Yes	Yes	No	Yes	Yes	Unclear	No	4/7
Schulz et al. 2013	Unclear	Unclear	No	Yes	Yes	Unclear	No	2/7
Severson et al. 2008	Unclear	Yes	Unclear	Yes	Yes	Unclear	No	2/7
Stanczyk et al. 2013	Yes	Yes	Unclear	Yes	No	Unclear	No	3/7
Strecher et al. 2008	Unclear	Yes	Yes	Yes	Yes	Yes	No	5/7
Stoddard et al. 2008	Yes	Yes	Yes	Yes	Yes	Yes	No	6/7
Stoops et al. 2009	Yes	Yes	No	No	Unclear	Unclear	No	3/7
Tensil et al. 2013	Yes	Yes	Yes	Yes	Yes	Unclear	No	5/7