Here are some factors to consider when you are evaluating a paper that reports on prognostic study:
- Was the sample of the patients representative of the illness or condition?
- Were the patients classified in homogeneous groups?
- Was the follow-up long enough to measure a clinical outcome?
- Was the follow-up complete?
- Were outcome measures "blind?"
- What are the risks of the outcome over time?
- How precise are the estimates?
Heneghan, C., & Badenoch, Douglas. (2006). Evidence-based medicine toolkit (2nd ed.). Malden, Mass. ; Oxford: BMJ Books/Blackwell Pub.