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8.3 Appendix 3 - Key to evidence statements2

1++ High quality meta-analyses, systematic reviews of randomized controlled trials RCTs, or RCTs with a
very low risk of bias

1+ Well conducted meta-analyses, systematic reviews, or RCTs with a low risk of bias
1- Meta-analyses, systematic reviews, or RCTs with a high risk of bias
2++ High quality systematic reviews of case control or cohort studies

High quality case control or cohort studies with a very low risk of confounding or bias and a high
probability that the relationship is causal
2+ Well conducted case control or cohort studies with a low risk of confounding or bias and a moderate
probability that the relationship is causal
2- Case control or cohort studies with a high risk of confounding or bias and a significant risk that the
relationship is not causal
3 Non-analytic studies, eg case reports, case series
4 Expert opinion

2 http://www.sign.ac.uk/guidelines/fulltext/50/annexoldb.html
guidelines.esgo.org | esgo-guidelines@esgomail.org
Published October 2016 by European Society of Gynaecological Oncology
Copyrights: © European Society of Gynaecological Oncology
ESGO Advanced (stage III-IV) Ovarian Cancer Surgery Quality Indicators_v2

 OVARIAN CANCER SURGERY - QUALITY INDICATORS 
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