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Table 2 Summary of risk of bias for randomised studies

From: The effectiveness of implementation strategies in improving preconception and antenatal preventive care: a systematic review

Study

Criteria for judging risk of bias for RCTs

Additional criteria for cluster RCTs

Other

Random sequence generation

Allocation concealment

Blinding of participants and personnel

Blinding of outcome assessment

Incomplete outcome data

Selective reporting

Recruitment to cluster

Baseline imbalance

Loss of clusters

Incorrect analysis

Compatibility with individual RCTs

 

Althabe et al. (2017) [71]

Low

Unclear

High

Unclear

Low

Low

Low

Low

Low

Low

Low

-

Bakker et al. (2003) [67]

Low

Unclear

High

High

High

Unclear

NA

NA

NA

NA

NA

-

Bar-Zeev et al. (2019) [52]

Unclear

High

High

High

High

Low

High

Unclear

High

Low

Unclear

-

Brownfoot et al. (2016) [53]

Low

Low

High

Unclear

Low

Unclear

NA

NA

NA

NA

NA

-

Campbell et al. (2006) [70] and Cooke et al. (2001) [69]

Unclear

Unclear

High

High

High

Unclear

NA

NA

NA

NA

NA

-

Hajek et al. (2001) [68]

Low

Unclear

High

Unclear

Low

Unclear

NA

NA

NA

NA

NA

-

Manfredi et al. (2011) [72]

Unclear

Unclear

High

Unclear

Unclear

Unclear

Low

Unclear

High

High

Unclear

-

Omer et al. (2020) [51]

Low

Low

High

Unclear

Low

Unclear

Low

Low

Low

Low

Unclear

-

Secker-walker et al. (1992) [73]

Unclear

Unclear

High

Unclear

Low

Unclear

NA

NA

NA

NA

NA

Higha

Tsoh et al. (2010) [74]

Low

Low

High

Unclear

Low

Unclear

NA

N/A

NA

NA

NA

Higha

  1. aHigh risk of contamination