Based on our co-publication, ‘Guidance to best practices for systematic reviews’, this invited review focusses on well-documented deficiencies of systematic reviews and briefly explains some of the reasoning behind current standards. These deficiencies are categorized by six principles of good scholarship. The visual abstract highlights these and serves as a timeline for the major tasks in developing a review. We refer interested readers to our Guidance article for details and references to source documents. This article also has a graphic abstract.