Emmanuel C Megafu, Michael N Megafu, Janet T Nguyen, Elisabeth Point Du Jour, Wesley H Bronson, James D Lin, Andrew C Hecht, Robert L Parisien
The Fragility of Statistical Findings in Cervical Disc Arthroplasty: a Systematic Review of Randomized Controlled Trials
Archives of orthopaedic and trauma surgery
estimating causal effects treatments randomized experiments generally considered gold standard nevertheless often infeasible conduct variety reasons ethical concerns excessive expense timeliness consequently much knowledge causal effects must come nonrandomized observational studies article advocate position observational studies designed approximate randomized experiments closely possible particular observational studies designed using background information create subgroups similar treated control units similar refers distributions background variables great importance activity conducted without access outcome data thereby assuring objectivity design many situations objective creation subgroups similar treated control units balanced respect covariates accomplished using propensity score methods theoretical perspective underlying position presented followed particular application context us tobacco litigation application uses propensity score methods create subgroups treated units male current smokers control units male never smokers least similar respect distributions observed background characteristics randomized collection subgroups approximate randomized block experiment respect observed covariates