Table C.3.

Levels of Evidence – Prognosis
Level 1 – Inception Cohort Studies	Level 1.a – Systematic review of inception cohort studies
	Level 1.b – Inception cohort study
Level 2 – Studies of All or None	Level 2.a – Systematic review of all or none studies
	Level 2.b – All or none studies
Level 3 – Cohort Studies	Level 3.a – Systematic review of cohort studies (or control arm of RCT)
	Level 3.b – Cohort study (or control arm of RCT)
Level 4 – Case Series/Case Controlled/Historically Controlled Studies	Level 4.a – Systematic review of Case series/Case Controlled/Historically Controlled studies
	Level 4.b – Individual Case series/Case Controlled/Historically Controlled study
Level 5 – Expert Opinion and Bench Research	Level 5.a – Systematic review of expert opinion
	Level 5.b – Expert consensus
	Level 5.c – Bench research/single expert opinion