6. Operative time small‐incision vs open cholecystectomy: all available data.
| Trial | Type of data | SIC ‐ mean/median | SIC ‐ SD/range | OC ‐ mean/median | OC ‐ SD/range | Skewness SIC | Skewness OC |
| Assalia 1993 | A ‐ SD | 60 | 8.7 | 59 | 8.5 | 6.90 | 6.94 |
| Coelho 1992a | A ‐ | 86 | ‐ | 99 | ‐ | ‐ | ‐ |
| Coelho 1993 | A ‐ range | 74 | 40 ‐ 125 | 86 | 40 ‐ 140 | ‐ | ‐ |
| O'Dwyer 1992a | A ‐ SD | 62 | 22 | 69 | 17 | 2.82 | 4.06 |
| Schmitz 1997a | A ‐ SD | 62 | 16 | 58 | 12 | 3.88 | 4.83 |
| Seenu 1994 | A ‐ range | 60 | 30 ‐ 100 | 65 | 20 ‐ 90 | ‐ | ‐ |
| Wani 2002 | A ‐ range | 74 | 40 ‐ 125 | 70 | 50 ‐ 125 | ‐ | ‐ |
| A: Average / mean | SD: standard deviation |