Table 2 Sources of uncertainty in STAs
|  | TCT | Non-TCT | χ2 (p) |
|---|---|---|---|
The external validity of clinical studies | |||
 Acceptable external validity | 36 (43.37%) | 39 (26.71%) | 7.2714 (0.026) |
 Moderate external validity | 37 (44.58%) | 90 (61.64%) | |
 Questionable external validity | 10 (12.05%) | 17 (11.64%) | |
 Total | 83 (100%) | 146 (100%) | |
Availability of direct treatment comparison | |||
 Not available | 28 (33.73%) | 43 (29.45%) | 1.1922 (0.551) |
 Some available | 28 (33.73%) | 45 (30.82%) | |
 All available | 27 (32.53%) | 58 (39.73%) | |
 Total | 83 (100%) | 146 (100%) | |
Maturity of survival data | |||
 Extremely immature | 29 (34.94%) | 56 (38.36%) | 7.2550 (0.027) |
 Immature | 35 (42.17%) | 38 (26.03%) | |
 Mature | 19 (22.89%) | 52 (35.62%) | |
 Total | 83 (100%) | 146 (100%) | |