The effects of spinal manipulation on performance-related outcomes in healthy asymptomatic adult population: a systematic review of best evidence

Table 2 Risk of bias table based on Scottish Intercollegiate Guidelines Network (SIGN) Criteria for high risk of bias studies; randomized controlled trials

Author, Year	Research Question	Randomization	Concealment	Blinding	Similarity at baseline	Similarity between arms	Outcome measures	Percent drop-out	Intention to treat	Results between sites	Level of evidence
Botelho et al., 2012	Y	Y	CS	N	N	N	Y	0%	NA	NA	1-
Cardinale et al., 2015	Y	Y	N	CS	Y	Y	CS	0%	NA	NA	1-
Enebo et al., 2003	Y	Y	CS	N	CS	CS	CS	0%	CS	NA	1-
Engel et al. 2007	Y	Y	Y	CS	N	N	CS	20%	N	NA	1-
Fox et al., 2006	Y	Y	CS	N	Y	Y	CS	CS	CS	NA	1-
Miller et al., 2000	Y	Y	N	N	Y	Y	CS	CS	Y	NA	1-
Nansel et al., 1992	Y	Y	CS	N	CS	CS	Y	0%	Y	NA	1-
Nansel et al., 1993	Y	Y	CS	Y	CS	Y	CS	0%	Y	NA	1-
Palmgren et al., 2009	Y	Y	Y	N	CS	Y	Y	0%	Y	NA	1-
Passmore et al., 2010	Y	Y	CS	Y	CS	CS	Y	0%	Y	NA	1-
Pollard et al., 1998	Y	Y	CS	CS	CS	CS	CS	CS	CS	NA	1-
Schwartzbauer et al., 1997	CS	Y	N	N	CS	CS	CS	25%	Y	NA	1-
Shrier et al., 2006	Y	Y	CS	CS	Y	Y	Y	17.6%	Y	NA	1-
Stamos-Papastamos et al., 2011	Y	Y	CS	N	Y	Y	Y	CS	Y	NA	1-
Straub et al., 2001	Y	Y	CS	CS	CS	CS	Y	0%	Y	NA	1-
Ward et al., 2012	N	Y	N	N	CS	CS	CS	5%	NA	NA	1-
Ward et al., 2013	Y	Y	Y	N	N	N	Y	0%	CS	NA	1-
Ward et al., 2014	Y	Y	N	N	Y	Y	N	0%	Y	NA	1-