At the beginning of December I had a query from a user who wanted to find negative research results regarding a topic she was using for her masters course.
I drew a complete blank so I asked a question of the Clinical Librarians email list, a source of amazing brain power.
I thought I would summarise the answers (with permission from the senders) as it is an interesting topic.
Most of us will have heard of publication bias, (https://en.wikipedia.org/wiki/Publication_bias) but what if we were asked to specifically find negative results?
A few resources were suggested:
Journal of Negative Results http://www.jnr-eeb.org/index.php/jnr
I also found the Journal of Negative Results in Biomedicine http://jnrbm.biomedcentral.com/
PLOS Negative Results collection http://collections.plos.org/missing-pieces
A few people pointed me in the direction of website and articles that discussed the topic:
Alltrials site http://www.alltrials.net/ – Alltrials is a campaign that was launched in January 2013 and calls for all past and present clinical trials to be registered and their results reported.
Hetherington, J. et al. Retrospective and prospective identification of unpublished controlled trials: lessons from a survey of obstetricians and paediatricians. Pediatrics. 1989 Aug;84(2):374-80 http://pediatrics.aappublications.org/content/84/2/374.long – an old article that begins the suggestion of prospective registration of trails being an option to help identify unpublished studies
Song F, Eastwood AJ, Gilbody S, Duley L, Sutton AJ. Publication and related biases. Health Technology Assessment 2000;4(10). http://www.journalslibrary.nihr.ac.uk/__data/assets/pdf_file/0005/64895/FullReport-hta4100.pdf
This gives a good overview of the topic of publication bias and points to statistical techniques to adjust for publication bias in systematic reviews. Chapter 7 covers the locating of unpublished trials
And I had a few search tips:
Cochrane Reviews – because Cochrane reviews have completed a thorough search, potentially they will have identified negative results.
The following search terms were suggested “no significant” adj5 “primary outcome” – I am sure that there could be any number of variations on this
Try Trial Registries e.g. https://clinicaltrials.gov/ – a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world.
I gave our requestor an overview of what I had found out and left her to search for negative results, this is because we don’t complete searches for people on academic courses. I just asked her if she found anything, she did by using a variety of search terms and following links.
It would be great to see any other suggestions in the Blog comments
Lucy Anderson BA (Hons) MCLIP
Knowledge Specialist: Outreach and Liaison
Pennine Care NHS Foundation Trust