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Table 3 Categories of additional non-standard RoB domains in Cochrane systematic reviews

From: The judgement of biases included in the category “other bias” in Cochrane systematic reviews of interventions: a systematic survey

Additional category

N of Cochrane reviews

Group similarity at baseline (selection bias)

11

Baseline data

5

Baseline outcome measures (similar)

3

Groups balanced at baseline/ balance in baseline characteristics

2

Baseline characteristics of participants

1

Baseline comparability of treatment and control groups

1

Baseline measures

1

Similarity of baseline characteristicsa

1

Treatment/control groups comparative at entry

1

Major imbalance in important baseline confounders

1

Comparability of groups on different prognostic characteristicsa

1

Size

8

Size of the study

5

Small sample size bias

4

Sample sizea

2

Sufficient sample sizea

1

Power calculationa

1

Timing of outcome assessment (similar)a

10

Adequate follow-up

2

Study duration

2

Early stopping

1

Groups received comparable treatment

2

Care program identical/ identical care

2

Treatment fidelitya

1

Free of systematic differences in care?a

1

Consistency in intervention delivery

1

Equality of treatment

1

Protocol deviation balanced

1

Groups received same intervention

1

Compliance/adherence assessed (acceptable)

7

Compliance with recommendation reliable?

1

Compliance acceptablea

1

Source of funding/ sponsorship

4

For profit fundinga

1

Fundinga

1

Vested interest bias

1

Conflict of interest

1

Co-intervention avoided or similara

5

Co-interventions

2

Groups received same co- interventions

1

Intention to treat

5

Incorrect analysis

1

Results based on data dredging?

1

Analyses adjust for different lengths of follow-up workers?

1

Appropriate statistical tests use?

1

Adequate adjustment for confounding in the analyses?

1

Contamination/ protection against contamination

3

Validity of outcome measures

1

Reliability of outcome measures

1

Outcome measures used valid and reliable?

1

Free from performance bias

1

Performance bias as «differential expertise» bias

1

Performance bias as comparability in the experience of care providers

1

Adequate patient description

1

Recruitment of participants from the same population?

1

Recruitment of participants over the same study period?

1

Washout/ carry-over effect in cross-over study designs

2

Overall assessment of bias risk

1

Summary of risk of bias for Consumption outcome

1

Researcher allegiancea

1

Therapist allegiancea

1

CHBG (Cochrane hepato-biliary group) combined assessment (mortality)a

1

CHBG combined assessment (hepatic encephalopathy)a

1

Comparability with individually randomized trials

1

Detection bias (biochemical validation of smoking outcomes)

1

Ethical approval

1

Explicit inclusion/exclusion criteria

1

Free of dietary differences other than fat?a

1

Loss of clusters

1

Methods for selecting cases to adjudicate

1

Outcome description

1

Publication format

1

Recruitment bias

1

  1. adomains found in 9 Cochrane reviews that had both ‘other bias’ domain and additional non-standard domain(s) for other bias in RoB tables