Table 1

The recommended classification and levels of evidence developed by the Chinese Stroke Association

Class I (benefit>>>risk)
The procedure/treatment should be implemented/administered.		Class IIa (benefit>>risk)
It is reasonable to conduct specialised research to implement/administer the procedure/treatment with specific objectives.		Class IIb (benefit≥risk)
Multiple studies are needed, and more registered data would be helpful. It may be worth considering the implementation/administration of the procedure/treatment.		Class III (risk=benefit or risk>benefit)
Level A

  • Multiple diverse populations were assessed.

  • The data are sourced from multiple RCTs or meta-analyses.

  • The recommended procedure/treatment is beneficial/effective.

  • Multiple RCTs or meta-analyses provide sufficient evidence.

  • The recommendation leans towards the usefulness/effectiveness of the procedure/treatment.

  • The evidence from multiple RCTs or meta-analyses is inconsistent.

  • The recommendation regarding effectiveness/efficacy has not been widely recognised.

  • The evidence from multiple RCTs or meta-analyses is highly inconsistent.

  • The recommended procedure/treatment is not beneficial/ineffective and may even be harmful.

  • Multiple RCTs or meta-analyses provide sufficient evidence.

Level B

  • The assessed population was limited.

  • The data are derived from a single RCT or non-randomised studies.

  • The recommended procedure/treatment is beneficial/effective.

  • The evidence from an RCT or non-randomised studies.

  • The recommendation leans towards the usefulness/effectiveness of the procedure/treatment.

  • The evidence from a single RCT or non-randomised studies is inconsistent.

  • The recommendation regarding effectiveness/efficacy has not been widely recognised.

  • The evidence from a single RCT or non-randomised studies is highly inconsistent.

  • The recommended procedure/treatment is not beneficial/ineffective and may even be harmful.

  • The evidence from an RCT or non-randomised studies.

Level C

  • The assessed population was extremely limited.

  • Expert consensus opinions, case studies or diagnostic/treatment guidelines.

  • The recommended procedure/treatment is beneficial/effective.

  • Expert consensus opinions, case studies or diagnostic/treatment guidelines.

  • The recommendation leans towards the usefulness/effectiveness of the procedure/treatment.

  • Expert opinions are divergent, case studies or diagnostic/treatment guidelines.

  • The recommendation regarding effectiveness/efficacy has not been widely recognised.

  • Expert opinions are divergent, case studies or diagnostic/treatment guidelines.

  • The recommended procedure/treatment is not beneficial/ineffective and may even be harmful.

  • Expert consensus opinions, case studies or diagnostic/treatment guidelines.

  • RCTs, randomised controlled trials.