E01¶


Research	R0050 — Journalism and Other Truth-Seeking Disciplines
Run	2026-03-31
Query	Q002
Source	SRC06
Evidence	SRC06-E01
Type	Analytical

OCEBM's five-level evidence hierarchy is a precursor to GRADE.

URL: https://www.cebm.ox.ac.uk/resources/levels-of-evidence/ocebm-levels-of-evidence

Extract¶

OCEBM ranks evidence in five levels by study type:

Level 1: Systematic reviews of RCTs
Level 2: Systematic reviews of less rigorous studies
Level 3: Non-randomized cohort studies
Level 4: Case-control and case series
Level 5: Mechanism-based reasoning

The framework organizes evidence quality by clinical question type (treatment, diagnosis, prognosis, etc.), providing question-specific hierarchies.

Novel concept assessment: OCEBM's core concept — ranking evidence by study type — is fully captured by GRADE, which evolved from OCEBM and similar frameworks. GRADE improves on OCEBM by adding explicit quality modifiers (risk of bias, imprecision, inconsistency, indirectness, publication bias) beyond just study type. The one potentially distinctive OCEBM feature is question-type-specific hierarchies, but GRADE also differentiates between treatment effects and diagnostic accuracy.

Relevance to Hypotheses¶

Hypothesis	Relationship	Strength
H1	Contradicts	OCEBM does not contribute novel concepts
H2	Supports	Another discipline whose concepts are captured
H3	Supports	Falls in the "already captured" category

Context¶

OCEBM and CASP are both EBM tools that predate GRADE and share its intellectual ancestry. Their concepts are captured by GRADE through direct descent rather than independent convergence.