Table 5 Validity, quality and impact of the individual study
ID | Internal validity | External validity | Quality of evidence for individual studies |
|---|---|---|---|
Berger et al, 2008 [24] | Fair | Fair | Medium |
Blank et al, 2014 [25] | Poor | Fair | Medium |
Bormann et al, 2006 [26] | Poor | Fair | Medium |
Brown et al, 2014 [27] | Fair | Fair | Medium |
Cade et al, 2010 [28] | Poor | Poor | Weak |
Chhatre et al, 2013 [29] | Fair | Poor | Weak |
Duncan et al, 2012 [30] | Fair | Poor | Medium |
Eller et al, 2013 [31] | Poor | Poor | Weak |
Fillipas et al, 2006 [32] | Fair | Fair | Medium |
Galantino et al, 2005 [33] | Poor | Poor | Medium |
Gayner et al, 2012 [34] | Fair | Fair | Medium |
Goujard et al, 2003 [35] | Poor | Poor | Medium |
Jones et al, 2007 [36] | Poor | Poor | Medium |
Lechner et al, 2003 [37] | Poor | Poor | Medium |
Li et al, 2010 [38] | Fair | Good | Strong |
Maharaj et al, 2011 [39] | Poor | Poor | Weak |
McCain et al, 2003 [40] | Poor | Poor | Medium |
Miles et al, 2003 [41] | Poor | Poor | Medium |
Molassiotis et al, 2002 [42] | Poor | Fair | Medium |
Mutimura et al, 2008 [43] | Fair | Poor | Medium |
Ogalha et al, 2011 [44] | Poor | Poor | Medium |
Proeschold-Bell et al, 2010 [45] | Poor | Poor | Medium |
Ruiz et al, 2010 [46] | Fair | Fair | Medium |
Sikkema et al, 2005 [47] | Fair | Good | Medium |
Tam et al, 2012 [48] | Fair | Fair | Medium |
Wang et al, 2010 [49] | Poor | Poor | Weak |
Webel, 2010 [50] | Fair | Poor | Medium |
Wu et al, 2006 [51] | Poor | Fair | Medium |