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. 2014 Jun;60(6):523–531.

Table 2.

Clinician level of obligation for recommendations from the American Academy of neurology: A modified Delphi approach was used to achieve consensus.

CATEGORY DEFINITION OR EXAMPLE
Modal modifiers used to indicate the final clinician level of obligation
  • Level A “Must”
  • Level B “Should”
  • Level C “Might”
  • Level U No recommendation supported
Initial rating of confidence in the evidence for each intervention outcome pair
  • High Requires 2 or more class I studies
  • Moderate Requires 1 class I study or 2 or more class II studies
  • Low Requires 1 class II study or 2 or more class III studies
  • Very low Requires only 1 class III study or 1 or more class IV studies
Classification of evidence for therapeutic intervention for risk of bias
  • Class I

  • The study is a randomized clinical trial

  • All relevant baseline characteristics are presented and substantially equivalent between treatment groups or there is appropriate statistical adjustment for differences

  • Outcomes measurement is objective or determined without knowledge of treatment status

  • The following also are required:
    1. the primary outcomes are defined,
    2. the inclusion criteria are defined,
    3. there is accounting for dropouts and crossovers (with at least 80% of enrolled subjects completing the study), and
    4. there is concealed allocation
  • Class II

  • The study is a cohort study meeting criteria a–c above or is a randomized controlled trial that lacks 1 or 2 of criteria a–d

  • All relevant baseline characteristics are presented and substantially equivalent among treatment groups, or there is appropriate statistical adjustment for differences

  • There is masked or objective outcome assessment
  • Class III

  • The study is a controlled study (including well-defined natural history controls or patients serving as their own controls)

  • The study includes a description of main confounding differences between treatment groups that could affect outcome

  • Outcome assessment is masked, objective, or performed by someone who is not a member of the treatment team
  • Class IV

  • The study does not include patients with the disease

  • The study does not include patients receiving different interventions

  • The study uses undefined or unaccepted interventions or outcome measures

  • No measures of effectiveness or statistical precision are presented or calculable

Adapted from Giza et al.3