Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Related Content +++ Quick Reference ++Table Graphic Jump LocationLevels of EvidenceaView Table||Download (.pdf) Levels of Evidencea Level of Evidence Grade Definition 1 A Independent blinded comparison of sign or symptom results with a criterion standard of diagnosis among a large number of consecutive patients suspected of having the target condition 2 B Independent blinded comparison of sign or symptom with a criterion standard of diagnosis among a small number of consecutive patients suspected of having the target condition 3 C Independent blinded comparison of sign or symptom with a criterion standard of diagnosis among nonconsecutive patients suspected of having the target condition 4 C Nonindependent comparison of sign or symptom with a criterion standard of diagnosis among samples of patients who obviously have the target condition plus, perhaps, normal individuals 5 C Nonindependent comparison of sign or symptom with a standard of uncertain validity aModified from Holleman and Simel.13 Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.