How do you assess the methodological quality of observational research studies?

What methods are available (such as scoring or rating scales) to assess the methodological quality of a scientific research article? I am interested in assessing observational studies, not randomized control trials.





Also, how would you go about calculating odds ratios? What study results would be necessary to calculate these if the authors do not provide them?





Thank you!

How do you assess the methodological quality of observational research studies?
ASSESSING OBSERVATION RESEARCH


Hartz A, Bentler S, Charlton M, Lanska D, Butani Y, Soomro GM, et al. Assessing observational studies of medical treatments. Emerg Themes Epidemiol 2005; 2: 8.


***** assesses various schema -- link may require membership or you might have to interlibrary loan -- but excellent review!


http://www.ete-online.com/content/2/1/8





Sorensen HT. Lash TL. Rothman KJ. Beyond randomized controlled trials: a critical comparison of trials with nonrandomized studies. [Review] [58 refs] Hepatology. 44(5):1075-82, 2006 Nov.


** focuses heavily on evaluating observational research





Laupacis A, Mamdani M. Observational studies of treatment effectiveness: some cautions. Ann Intern Med 2004; 140: 923-924.


** canonical article on observation





Ioannidis JP, Haidich AB, Pappa M, Pantazis N, Kokori SI, Tektonidou MG, et al. Comparison of evidence of treatment effects in randomized and nonrandomized studies. JAMA 2001; 286: 821-830.





Benson K, Hartz AJ. A comparison of observational studies and randomized, controlled trials. N Engl J Med 2000; 342: 1878-1886.





CALCULATING ODDS RATIOS


Try the wikipedia article and its links


http://en.wikipedia.org/wiki/Odds_ratio