| Reference | Population | Method of record selection | Method of review | More than one adverse event per patient? | Time frame of included events | Kappa value for interobserver agreement | Endpoints |
| 1. Brennan et al25 32 | Acute-care hospital patients (no psychiatric patients) | Random sample of hospitalisations from 51 hospitals | Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by two physicians | Not specified | Occurred before and during and detected during index admission | 0.61 | Incidence, negligence, outcome, location, type of event |
| 2. O’Neil et al23 28 | Hospital patients | All admissions to the medical service of one hospital over a 4-month period | 1. Two-stage record review: first, screening for one of 15 criteria by medical-record analysts; second, review by physician | No | Not specified | 0.57 | Incidence, preventability |
| 2. Reviewing reported incidents | |||||||
| 3. Wilson et al3 | Acute-care hospital patients (no psychiatric or day-care patients) | Random sample of admissions from 28 hospitals | Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by two medical officers | No | Occurred before* and during and detected during or after index admission | 0.55 | Incidence, preventability, outcome, provider of care, location, type of event |
| 4. Thomas et al2 | Hospital patients (no psychiatric, rehabilitation or drug/alcohol treatment patients) | Random sample of discharges from 28 hospitals | Two-stage record review: first, screening for one of 15 criteria by trained nurses; second, review by physician | No | Occurred before and during and detected during index admission | 0.4 | Incidence, negligence, outcome, provider of care, location, type of event |
| 5. Vincent et al26 33 | Acute hospital patients (general medicine, general surgery, orthopaedic surgery, obstetrics) | Records randomly drawn from two hospitals | Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by clinician | Yes | Not specified | Not specified | Incidence, preventability, outcome, provider of care, type of event |
| 6. Davis et al24 30 | Hospital patients (no psychiatric, day-care or rehabilitation patients) | Random sample of admissions from 13 hospitals | Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by medical officer | Not specified | Occurred before* and during and detected during index admission | 0.47 | Incidence, preventability, outcome, provider of care, location, type of event |
| 7. Baker et al31 | Hospital patients (no paediatric, psychiatric, obstetric or rehabilitative) | Random sample of admissions from 20 hospitals | Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by physician | Yes | Occurred before and during and detected during or after index admission† | 0.47/0.45/0.69‡ | Incidence, preventability, outcome, provider of care, type of event |
| 8. Sari et al29 | Hospital patients (surgery, general medicine, elderly care, orthopaedics, urology, oncology, ENT, ophthalmology) | Random sample of admissions in one hospital | 1. Two-stage record review: first, screening for one of 18 criteria by trained nurses; second, review by physician | Yes | Not specified | 0.76 | Incidence |
| 2. Reviewing reported incidents |
*Only included if (partly) responsible for index admission.
†Only included if occurred/was detected during a hospital admission.
‡Kappa values for interobserver agreement of judgement on injury/causation/preventability.