Risk of bias assessment and different tools used to assess systematic review - Pubrica
                     WHAT IS THE RISK OF BIAS 
 ASSESSMENT AND  
DIFFERENT TOOLS USED 
TO  ASSESS SYSTEMATIC 
REVIEW
An Academic presentation by
Dr. Nancy Agens, Head, Technical Operations, 
Pubrica  Group: www.pubrica.com
Email: [email protected]
Today's 
Discussion
Outlin In brief
Introduction  
e
Quality 
Assessment
Tools used to Assess the Risk of Bias in the Systematic 
Review  How to Assess the Risk of Bias
Determining an Appropriate Risk of Bias Assessment 
Tool  Conclusion
In 
Brief
The risk of bias is defined as the risk of systematic error or a  
deviation from reporting the truth or an appropriate evidence 
finding.  It occurs when there is a systematic flaw or limitations in 
the study  design or the conduct of the study. This article describes 
different  assessment tools and the types of study designs for 
which the tool  is applicable along with the flow of how to avoid the 
risk of bias.
Introductio
n
A systematic review guideline will often determine the study design to answer the  
formulated question, and it is not enough in trusting the evidence of systematic review 
 over observational studies.
There are several terms like quality assessment, critical appraisal, or internal validity, 
 which are used for the evaluation of studies supported by the guideline.
In the risk of bias, the bias determines the factor that can affect the observations and  
findings of the study systematically and report it to be different from the actual conclusion.
Inadequate study design or the conduct of the study will give false findings which result in 
 wasting time and resources, and missing opportunity for effective intervention.
Quality 
Assessment
Quality assessment or risk of bias assessment helps in regulating and establishing  
transparency of evidence synthesis and findings and it is often performed for each study 
 in a review; thus the collected evidence eliminate bias in the outcomes.
The risk of bias assessment can be done by professionals who may be conducted by the 
 guideline development group or requires a methodological expert or by experiences  sy
stematic review researchers. There are three types of bias they are,
Selection bias – Participant or Population comparability in a study.
Performance bias – The influence of estimate effect.
Reporting bias – Problems with measurements or classification of outcome.
Tools used to Assess the Risk of 
Bias in  the Systematic Review:
AMSTAR 2 - A MeaSurement Tool to Assess systematic Reviews
AHRQ RRB - AHRQ tool for evaluating the Risk of Reporting Bias  
AHRQ ORB – AHRQ Outcome and analysis Reporting Bias framework
GRADE – Grading of Recommendations Assessment, Development and
 Evaluation
SAQAT – Semi-Automated Quality Assessment Tool
NOS - Newcastle-Ottawa Scale
AXIS – Appraisal tool for Cross-Sectional Studies
Contd..
QUIPS - Quality In Prognosis Studies tool
RoB 1.0 – Cochrane Risk of Bias tool for randomized trials
RoB 2.0 - Revised tool for Assessing Risk of Bias in randomized trials
SciRAP - Science in Risk Assessment and Policy
SIGN - The Scottish Intercollegiate Guidelines Network
RoBANS - Risk of Bias Assessment Tool for Nonrandomized Studies 
 QUADAS 2 - Quality Assessment of Diagnostic Accuracy Studies  
PROBAST - Prediction model Risk Of Bias ASsessment Tool
OHAT - Office of Health Assessment and Translation
Downs Black - Downs Black tool
How to Assess the Risk of 
Bias?
1.Plan your approach
2.Identifying an appropriate risk of bias assessment tool
3.Be aware of related issues
4.Appraise each study
5.Report the assessment process
6.Use your appraisals to inform the guideline
Determining 
an  
Appropriate 
Risk  of Bias  
Assessment 
Tool:
Contd
..

Conclusio
n
In summary, risk of bias assessment is a tool used to regulate findings which are 
 accurate and appropriate, and it is essential to select the risk of bias tool rightly.
There are many researches available to help, and it makes things easier to find 
 appropriate tools for assessing the risk of bias.
This article describes different assessment tools for a systematic review and  
the types of study designs for which the tool is applicable along with the flow of 
 how to avoid the risk of bias.
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