Table 6.
Effect direction plot for learning conditions (k = 32).
| Studies | Sample size (E/C) | Approach | Spacing | Outcomes |
|---|---|---|---|---|
| Tan and Nicholson (1997) | 42 | Intentional learning | N/A | ▴ |
| Nakata (2008) | 67/74# | Intentional learning | Spaced learning | ▲ |
| Başoglu and Akdemir (2010) | 29/29 | Intentional learning | Spaced learning | ▴ |
| Oberg (2011) | 28/36# | Intentional learning | N/A | ▴ |
| Azabdaftari and Mozaheb (2012) | 40/40# | Intentional learning | Spaced learning | ▴ |
| Komachali and Khodareza (2012) | 25/25 | Intentional learning | Spaced learning | ▴ |
| Kuo and Ho (2012) | 30/30# | Intentional learning | Massed and spaced learning | ▴ |
| Chien (2013) | 76 | Intentional learning | Spaced learning | ◀▶ |
| Nikoopour and Kazemi (2014) | 109 | Intentional learning | Spaced learning | ◀▶ |
| Barkat and Aminafshar (2015) | 15/15# | Intentional learning | Spaced learning | ▴ |
| Chien (2015) | 64 | Intentional learning | Spaced learning | ◀▶ |
| Hamzehbagi and Bonyadi (2015) | 30/30 | Intentional learning | N/A | ◂▸ |
| Lavoie (2016) | 39/15 | Intentional learning | Spaced learning | ▴ |
| Özer and Koçoglu (2015) | 89 | Incidental learning | Spaced learning | ◀▶ |
| Galedari and Basiroo (2016) | 30/30 | Intentional learning | Spaced learning | ▴ |
| Aminafshar (2017) | 15 | Intentional learning | Spaced learning | ◂▸ |
| Saputri (2017) | 13 | Intentional learning | Spaced learning | ▴ |
| Wu et al. (2017) | 10/10 | Intentional learning | Massed learning | ▴ |
| Kose and Mede (2018) | 17/17 | Intentional learning | Spaced learning | ▴ |
| Tsai (2018) | 9/9# | Intentional learning | Massed learning | ▴ |
| Chen and Chan (2019) | 48/50 | Intentional learning | Spaced learning | ▴ |
| Fukushima (2019) | 30 | Intentional learning | Spaced learning | ▴ |
| Reynolds and Shih (2019) | 100 | Intentional learning | Spaced learning | ▲ |
| Alhuwaydi (2020) | 42 | Intentional learning | N/A | ▴ |
| Hidayat and Yulianti (2020) | 27/26# | Intentional learning | Spaced learning | ◂▸ |
| Lai et al. (2020) | 38/20 | Intentional learning | Spaced learning | ▴ |
| Lukas et al. (2020) | 52 | Intentional learning | Spaced learning | ▲ |
| Reynolds et al. (2020) | 50 | Intentional and incidental learning | Spaced learning | ▲ |
| Samad and Makingkung (2020) | 20 | Intentional learning | N/A | ◂▸ |
| Wulandari and Musfiroh (2020) | 34/33 | Intentional learning | N/A | ▴ |
| Yüksel et al. (2020) | 57 | Intentional learning | Spaced learning | ▲ |
| Xodabande et al. (2021) | 36/19 | Intentional learning | Spaced learning | ▴ |
E, experimental group; C, control group. # = an experimental group, i.e., the least interfering experimental group, was treated as a control group. N/A = not available in the publication or from the authors. ▴ or ▲ = positive effect, ▾ = negative effect, ◀▶ or ◂▸ = no change. Large arrow = sample size equals or >50, small arrow = sample size smaller than 50.