Table 3. Outline of studies prior to 2008
Author             Year Overall risk of bias Outcome Level* Findings Follow up duration
1 2A 2B 3 4A 4B
Naji                     1986 Low ✓ ✓ Positive Unclear
Edwards, Kissling and Brennan 1988 Low ✓ Positive 2.5 years
Dunnington 1998 Low ✓ ✓ ✓ Varied 6-7 months
Morrison 2003 Low ✓ ✓ Positive 6 months
Morrison 2004 Low ✓ ✓ Positive 6 months
D’eon 2004 Low ✓ Positive 6 months
Brown 1971 Mod ✓ ✓ Positive <1 month
Lawson 1980 Mod ✓ ✓ Positive 3 months
Jewett 1982 Mod ✓ ✓ Positive 6-12 months
Greenberg 1984 Mod ✓ Positive 9 months
Edwards 1986 Mod ✓ Positive 18-24 months
Edwards, Kissling and Plauche 1988 Mod ✓ ✓ ✓ ✓ Positive Unclear
Snell     1989 Mod ✓ ✓ ✓ Positive 8 months
Bing-You 1990 Mod ✓ ✓ Varied 2-11 months
Katzelnick 1991 Mod ✓ ✓ ✓ Positive 8 months
Litzelman 1994 Mod ✓ ✓ Positive 6 months
Roberts 1994 Mod ✓ ✓ ✓ Positive 6 months
Susman and Gilbert 1995 Mod ✓ ✓ Positive <1 month
Spickard 1996 Mod ✓ ✓ ✓ Varied 8 months
Bing-You 1997 Mod ✓ ✓ ✓ Positive 12 months
Barth 1997 Mod ✓ Positive Unclear
Wipf 1999 Mod ✓ Positive 3 years
Furney 2001 Mod ✓ ✓ ✓ Positive 1 month
Mass                   2001 Mod ✓ Positive Unclear
Thomas          2002 Mod ✓ ✓ ✓ Positive 6 weeks
Frattarelli and Kasuya 2003 Mod ✓ ✓ Negative 6 months
Pandachuck 2004 Mod ✓ ✓ Positive Unclear
Hammoud 2004 Mod ✓ ✓ Positive 9 months
Busari 2006 Mod ✓ ✓ Positive 3-4 months
Gaba 2007 Mod ✓ ✓ ✓ Positive 6 months
Rubak 2008 Mod ✓ ✓ Positive 6 months
Aiyer           2008 Mod ✓ ✓ ✓ ✓ Positive Unclear
White 1997 High ✓ ✓ Positive 10 weeks
Jafri 2007 High ✓ ✓ ✓ Positive 1 month
Moser 2008 High ✓ Positive At 6 and 9 months
  16 18 18 21 2 1
  39 39 39 39 39 39
 Percentage 41 46 46 54 5 3

*Kirkpatrick levels as described by Hill et al. 200919

 Int J Med Educ. 2016; 7:25-31; doi: 10.5116/ijme.5685.14da