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. 2021 Oct 9;11:04048. doi: 10.7189/jogh.11.04048

Table 1.

Risk of bias assessment criteria

Definition of the risk of bias criterion
Risk-of-bias (rating score)
Source of data for maternal death in the study (information bias)
Completeness of cause-of-death data in the study (missing data bias)
Use of ICD-MM in assigning the causes of death in the study (selection bias)
Competence level of persons who assigned the causes of death (measurement bias)
Low (1)
Health facility records
≥90% deaths assigned causes
Use of ICD-MM definition stated
Expert panels / MDSR committees
Medium (2)
MDSR audits
75-90% deaths assigned causes
Not stated but data collected 2015 onwards
Primary clinical assessments in facility records
High (3)
Community surveys with VAs
<75% deaths assigned causes
Not stated and data collected 2010 to 2014
Not stated
Rationale for ratings Health facility records contain all details of events leading to the death. MDSR audits contain summaries, and VA reports lack clinical detail. The rating looks at increasing the risk of bias. WHO recommends ≥75% completeness to rate the data as reasonable for use in review studies. Mention of ICD-MM use assures that the standard definitions and classification of the causes of death was followed. Data from 2015 gives near assurance, and data before that may not have used ICD-MM classification. Deaths assessed by an expert or CEMD/MDSR committees are more comprehensive and accurate in their assessments. Facility clinical assessments may be biased or less competent.

VA – verbal autopsy, CEMD/MDSR – confidential enquiry into maternal deaths/maternal death surveillance and response