Table 7.
Effect direction plot for proficiency level of learners (k = 17).
| Studies | Sample size (E/C) | Proficiency level of learners | Outcomes |
|---|---|---|---|
| Tan and Nicholson (1997) | 42 | A1 | ▴ |
| Nakata (2008) | 67/74# | B1 | ▲ |
| Başoglu and Akdemir (2010) | 29/29 | B1 | ▴ |
| Oberg (2011) | 28/36# | B2 | ▴ |
| Azabdaftari and Mozaheb (2012) | 40/40# | C1 | ▴ |
| Komachali and Khodareza (2012) | 25/25 | B1 | ▴ |
| Chien (2013) | 76 | B1 | ◀▶ |
| Chien (2015) | 64 | B1 | ◀▶ |
| Hamzehbagi and Bonyadi (2015) | 30/30 | A2 | ◂▸ |
| Özer and Koçoglu (2015) | 89 | A1 | ◀▶ |
| Kose and Mede (2018) | 17/17 | B1 | ▴ |
| Fukushima (2019) | 30 | B1 | ▴ |
| Reynolds and Shih (2019) | 100 | B2 | ▲ |
| Alhuwaydi (2020) | 42 | B2 | ▴ |
| Hidayat and Yulianti (2020) | 27/26# | A1 | ◂▸ |
| Reynolds et al. (2020) | 50 | A1 | ▲ |
| Yüksel et al. (2020) | 57 | B1 | ▲ |
E, experimental group; C, control group. # = an experimental group, i.e., the least interfering experimental group was treated as a control group. ▴ or ▲ = positive effect, ▾ = negative effect, ◀▶ or ◂▸ = no change. Large arrow = sample size equals or >50, small arrow = sample size smaller than 50.