Just 1 out of 10 treatments backed by high-quality evidence
Quality of studies behind most healthcare interventions 'remains low' and needs to lift: authors
Only one in 10 medical treatments are backed by high-quality evidence, according to a review of Cochrane findings. 
International researchers looked at the primary outcome of 151 Cochrane systematic reviews published between 2015 and 2019 that were updates of earlier (2013-14) reviews to see whether the quality of evidence had improved over time.