Is this evidence about prognosis valid?

 

Was a defined, representative sample of patients assembled at a common (usually early) point in the course of their disease? Was patient follow-up sufficiently long and complete? Were objective outcome criteria applied in a “blind” fashion? If subgroups with different prognoses are identified Was there an adjustment for important prognostic factors? Was there validation in an independent group of “test-set” patients?

Reference: Evidence-based Medicine – Sackett, Richardson, Rosenberg and Haynes.