Table 1 List of studies included in this review
Sample size | Scale | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Article | Article type | Method | Total PhD n | Male n | Female n | Other n | Age M(SD) | Universities | Countries | Lead country |
Acker et al. (2015) [36] | P | Qualitative | 27 | 5 | 22 | 0 | -(−) | Single | Single | Canada |
Appel et al. (2003) [37] | P | Mixed | 159 | 77 | 82 | 0 | -(−) | Single | Single | Sweden |
Bauer (2016) [48] | D | Quantitative | 118 | 28 | 90 | 0 | -(−) | Multiple | Single | USA |
Bazrafkan et al. (2016) [41] | P | Qualitative | – | – | – | – | 32(9) | Multiple | Single | Iran |
Begun et al. (2017) [49] | P | Mixed | 281 | 219 | 60 | 2 | 38(9) | Multiple | Single | USA |
Benjamin et al. (2017) [50] | P | Qualitative | 29 | 11 | 18 | 0 | -(−) | Multiple | Single | USA |
Benesek (1998) [51] | D | Quantitative | 66 | 11 | 55 | 0 | -(−) | Multiple | Single | USA |
Bireda (2015) [52] | P | Qualitative | 5 | 0 | 5 | 0 | -(−) | Single | Single | Ethiopia |
Bolliger et al. (2012) [53] | P | Quantitative | 84 | - | - | - | 42(−) | Single | Single | USA |
Cole (2008) [54] | D | Quantitative | 261 | 98 | 161 | 0 | -(−) | Multiple | Multiple | - |
Cotterall (2013) [42] | P | Qualitative | 6 | 3 | 3 | 0 | -(−) | Single | Single | Australia |
Devine et al. (2017) [55] | P | Mixed* | 183 | 33 | 150 | 0 | 33(6) | Multiple | Multiple | Canada |
Devonport et al. (2014) [38] | P | Qualitative | 2 | 2 | 0 | 0 | 27(−) | Single | Single | UK |
Drake (2010) [56] | D | Quantitative | 220 | 40 | 180 | 0 | 28(5) | Multiple | Single | USA |
Dumitrescu (2016) [57] | D | Quantitative | 153 | 37 | 115 | 1 | 34(8) | Multiple | Single | USA |
El-Ghoroury et al. (2012) [58] | P | Quantitative | 209 | – | – | – | -(−) | Multiple | Single | USA |
Enzor (2017) [39] | D | Qualitative | 10 | 2 | 8 | 0 | -(−) | Multiple | Single | - |
Haynes et al. (2012) [59] | P | Qualitative | 8 | 0 | 8 | 0 | -(−) | Single | Single | USA |
Hill (2010) [60] | D | Quantitative | 64 | 29 | 35 | 0 | -(−) | Single | Single | USA |
Holahan (1979) [61] | P | Quantitative | 377 | 0 | 377 | 0 | -(−) | Single | Single | USA |
Hunter et al. (2016) [62] | P | Mixed* | 186 | 150 | 36 | 0 | 33(7) | Multiple | Multiple | Canada |
Kaufman (2004) [43] | D | Mixed | 41 | 7 | 33 | 0 | 41(−) | Single | Single | USA |
Kaufman (2006) [63] | P | Quantitative | 41 | 7 | 34 | 0 | 41(−) | Single | Single | USA |
Kenty (2000) [44] | P | Mixed | 111 | 0 | 111 | 0 | 45(43) | Multiple | Single | USA |
Kurtz-Costes et al. (2006) [40] | P | Qualitative | 20 | 8 | 12 | 0 | -(−) | Single | Single | USA |
Levecque et al. (2017) [64] | P | Quantitative | 3659 | – | – | – | 28(5) | Multiple | Single | Finland |
Lonka et al. (2014) [65] | P | Quantitative | 669 | 168 | 496 | 0 | 39(-) | Single | Single | Finland |
Lowe (2015) [66] | D | Quantitative | 338 | 60 | 276 | 2 | -(-) | Multiple | Single | USA |
Marais et al. (2018) [67] | P | Quantitative | 136 | 36 | 100 | 0 | -(−) | Single | Single | France |
Martinez et al. (2013) [68] | P | Qualitative | 5 | – | – | – | -(−) | Single | Single | USA |
McGregor et al. (2008) [69] | P | Quantitative | 10 | 3 | 7 | 0 | -(−) | Single | Single | USA |
Nelson (2014) [70] | D | Quantitative | 156 | 47 | 109 | 0 | -(−) | Multiple | Single | USA |
Nottingham (2017) [71] | D | Quantitative | 116 | 40 | 76 | 0 | -(−) | Multiple | Single | USA |
Orozco (2014) [72] | D | Quantitative | 161 | 23 | 138 | 0 | -(−) | Single | Single | USA |
Peters (2007) [73] | D | Quantitative | 104 | 24 | 79 | 0 | -(−) | Single | Single | USA |
Pifer et al. (2014) [74] | P | Qualitative | 31 | 17 | 14 | 0 | 33(−) | Single | Single | USA |
Platt et al. (1995) [75] | P | Quantitative | 53 | – | – | – | -(−) | Single | Single | USA |
Pychyl (1995) [76] | D | Mixed* | 19 | 8 | 11 | 0 | -(−) | Single | Single | Canada |
Pychyl et al. (1998) [77] | P | Mixed | 81 | 36 | 45 | 0 | 35(−) | Single | Single | Canada |
Rocha-Singh (1994) [78] | P | Quantitative | 469 | 178 | 291 | 0 | -(−) | Single | Single | USA |
Scheidler (2008) [79] | D | Quantitative | 507 | 141 | 363 | 3 | 42(−) | Multiple | Single | USA |
Scrubb (1997) [45] | D | Mixed | 156 | 80 | 76 | 0 | -(−) | Single | Single | USA |
Sekas et al. (1980) [80] | P | Quantitative | 42 | – | – | – | -(−) | Single | Single | USA |
Stubb et al. (2011) [81] | P | Mixed | 669 | 168 | 496 | 0 | 39(−) | Single | Single | Finland |
Stubb et al. (2012) [82] | P | Mixed | 669 | – | – | – | -(−) | Single | Single | Finland |
Ülkü-Steiner et al. (2000) [83] | P | Quantitative | 714 | 293 | 421 | 0 | -(−) | Single | Single | USA |
Usman Yousaf et al. (2016) [46] | P | Qualitative | 8 | – | – | – | -(−) | Single | Single | Malaysia |
Volkert et al. (2018) [84] | P | Quantitative | 835 | – | – | – | -(−) | Multiple | Single | USA |
Waaijer et al. (2016) [85] | P | Quantitative | 218 | 111 | 107 | 0 | -(−) | Single | Single | Netherlands |
Wang et al. (2010) [86] | P | Qualitative | 1 | 1 | 0 | 0 | 30(N/A) | Single | Single | Taiwan |
Williams (2014) [87] | D | Quantitative | 140 | 37 | 101 | 2 | 29(6) | Multiple | Single | USA |
Wright (2006) [88] | P | Quantitative | 15 | 7 | 8 | 0 | -(−) | Single | Single | UK |