Soni PD, et al. - In order to produce objective data for factors that can adequately lower bias and give accurate results in comparative efficacy research conducted using population registries, researchers analyzed if there was a link between survival hazard ratio approximations offered by the observational studies and randomized trials comparing treatment regimens for any diagnosis of cancer. Eligibility criteria were met by 350 treatment comparisons, which were matched to 121 randomized trials. No modifiable factor could be identified in population-based observational studies that improved agreement with randomized trials. Irrespective of reporting quality or statistical rigor of the observational study, findings revealed no agreement beyond what was expected by chance.