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Outcome Reporting Bias in Trials


ORBIT classifications (benefit outcomes)

DOWNLOADS: Benefit Classifications (WORD | PDF)

The ORBIT classification system for missing or complete outcome reporting in benefit outcomes

 

Classification

 Description

Level of reporting

Risk of bias*

Clear that the outcome was measured and analysed

A

Trial report states that outcome was analysed but only reports that result was not significant (typically stating p-value>0.05).

Partial

High Risk

B

Trial report states that outcome was analysed but only reports that result was significant (typically stating p-value<0.05).

Partial

No Risk

C

Trial report states that outcome was analysed but insufficient data were presented for the trial to be included in meta-analysis or to be considered to be fully tabulated.

Partial

Low Risk

D

Trial report states that outcome was analysed but no results reported.

None

High Risk

Clear that the outcome was measured

E

Clear that the outcome was measured. Judgment says outcome likely to have been analysed but not reported because of non-significant results.

None

High Risk

F

Clear that the outcome was measured. Judgment says outcome unlikely to have been analysed.

None

Low Risk

Unclear whether the outcome was measured

G

Not mentioned but clinical judgment says likely to have been measured and analysed but not reported on the basis of non-significant results.

None

High Risk

H

Not mentioned but clinical judgment says unlikely to have been measured at all.

None

Low Risk

Clear that the outcome was not measured

I

Clear that the outcome was not measured.

NA

No Risk

 

*Risk of bias arising from the lack of inclusion of non-significant results when a trial was excluded from a meta-analysis or not fully reported in a review because the data were unavailable.