Frequency and characteristics of promissory conference abstracts, i.e. abstracts without results, accepted at Cochrane Colloquia 1994-2020.

BACKGROUND The purpose of a conference abstract is to summarize the main points of a research-related report that will be presented at an academic conference. However, some conferences accept and publish abstracts without results, which is contrary to the basic idea of a conference abstract as a dissemination tool. A conference abstract without results included is called a "promissory abstract". This study aimed to analyze the frequency and characteristics of promissory conference abstracts, i.e. abstracts submitted without results, accepted at Cochrane Colloquia. METHODS We analyzed 8297 conference abstracts accepted at 25 Cochrane Colloquia, organized in 1994-2020, which were publicly available on the website of the Cochrane Library. Two authors screened abstracts to identify promissory abstracts. We extracted characteristics of promissory abstracts. RESULTS Among abstracts accepted for Cochrane Colloquia, 8.7% were promissory; 475 (66%) were accepted as poster presentations, 241 (34%) as oral presentations and 1 as a workshop. The median number of authors in promissory abstracts was 4 (interquartile range: 3 to 6 authors). In 245 (34%) promissory abstracts, affiliations of authors were not reported. The authors were most commonly affiliated with the following countries: UK (472; 36%), Canada (N = 123; 26%), China (N = 76; 16%), United States (N = 66; 14%) and Australia (N = 53; 11%). There were 512 (71%) promissory abstracts in which study design was not reported. CONCLUSION Promissory abstracts were commonly accepted at Cochrane Colloquia. Such abstracts deserve further attention, as they are detrimental in terms of the dissemination of new knowledge presented at a conference. Conference organizers could ask authors to update the abstract results subsequently to enable the dissemination of information presented at a conference.