Effectiveness and Safety of Acupuncture for Migraine: An Overview of Systematic Reviews

Table 3

Tabular presentation of risk of bias of included SRs.

Review	Phase 2			Phase 3
	1. Study eligibility criteria	2. Identification and selection of studies	3. Data collection and study appraisal	4. Synthesis and findings	Risk of bias in the review
Gao (2011)	☺	☹	?	☺	☹
Zheng (2012)	☺	☺	☺	☹	☹
Chen (2014)	☺	☺	☺	☺	☺
Yang (2014)	☺	☹	☹	☹	☹
Zhao (2014)	☹	☹	☺	☺	☹
Dai (2015)	☺	☹	☹	☹	☹
Yang (2015)	☺	☺	☺	☺	☺
Linde (2016)	☺	☺	☺	☺	☺
PuJ (2016)	☹	☹	☺	☹	☹
Pu (2016)	☺	☺	☺	☺	☺
Song (2016)	☺	☺	☺	☺	☺
Xian (2016)	☺	☺	☺	☹	☺
Zhao (2016)	☺	☺	☺	☺	☺
Xu (2018)	☺	☺	☺	☹	☺
Lu (2019)	☺	☺	☺	☹	☺

☺ = low risk; ☹ = high risk; ? = unclear risk.