Table 4.
Top 10 ranking for countries in 2019 based on the proportion of trials with a low risk of bias
| Trials with low risk of bias (%)† | No. of trials | Rank on the basis of no. trials per 107 inhabitants | Impact factor* | Adequate generation of allocation | Adequate concealed allocation | Intention-to-treat analysis | Adequate handling of drop-outs | |
|---|---|---|---|---|---|---|---|---|
| 1 UK | 57.1 | 15 | 19 | 3.37 (2.02–21.94) | 93.3 | 73.3 | 66.7 | 73.3 |
| 2 Netherlands | 51.9 | 27 | 2 | 4.28 (2.72–14.78) | 85.2 | 88.9 | 66.7 | 77.8 |
| 3 Finland | 38.5 | 13 | 1 | 4.50 (2.48–10.48) | 61.5 | 92.3 | 53.9 | 76.9 |
| 4 Korea | 30.0 | 20 | 44 | 2.11 (1.47–4.12) | 85.7 | 60.0 | 43.8 | 80.0 |
| 5 Germany | 27.3 | 11 | 27 | 4.84 (3.18–6.26) | 63.6 | 54.6 | 72.7 | 81.8 |
| 6 Spain | 26.7 | 15 | 15 | 3.15 (2.20–5.68) | 86.7 | 73.3 | 46.7 | 73.3 |
| 7 USA | 22.0 | 50 | 24 | 3.61 (1.98–8.76) | 60.0 | 70.0 | 36.0 | 70.0 |
| 8 Japan | 20.0 | 35 | 16 | 2.39 (1.88–6.08) | 54.3 | 51.4 | 34.3 | 77.1 |
| 9 China | 16.0 | 81 | 39 | 2.24 (1.70–3.65) | 59.3 | 51.9 | 21.1 | 55.6 |
| 10 Italy | 12.5 | 16 | 17 | 2.00 (0.77–5.53) | 62.5 | 56.3 | 25.0 | 68.8 |
*Values are median (i.q.r.) 2019 impact factors. Only countries with at least 10 published trials were analysed. †Trial with adequate generation of allocation, adequate concealment of allocation, intention-to-treat analyses, and adequate handling of drop-outs.