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Table 3 Guidance for assessing risk of performance bias at different study designs

From: What are the effects of control of mosquitoes and other nematoceran Diptera using the microbial agent Bacillus thuringiensis israelensis (Bti) on aquatic and terrestrial ecosystems? A systematic review protocol

Study design

Source of performance bias

Reported or suspected

Risk of performance bias

BA

Confounding factor or time-related trend

Yes

High/probably high

No

Low/probably low

Unclear

Unclear

CI and BACI

Confounding factor or contamination of study groups

Yes

High/probably high

No

Low/probably low

Unclear

Unclear

Time-related trend

Yes or No

Low (N/A for CI)