Interesting website: The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses (GA Wells, B Shea, D O'Connell, J Peterson, V Welch, M Losos, P Tugwell). If you are conducting a systematic overview of nonrandomized studies, you need an objective method for evaluating the quality of these studies. The Newcastle-Ottawa scale provides a numeric score that you can use for excluding low quality studies, giving greater weight to higher quality studies, or for sensitivity analysis. Category: Interesting websites, Category: Observational studies. This website was last verified on August 7, 2007. URL: www.ohri.ca/programs/clinical_epidemiology/oxford.htm