Publication bias in qualitative research: what becomes of qualitative research presented at conferences?

Less than half of studies presented at conferences remain unpublished two years later, and these studies differ systematically from those that are published. In particular, the unpublished studies are less likely to report statistically significant findings, and this introduces publication bias. This has been well documented for quantitative studies, but has never been explored in relation to qualitative research.

We reviewed the abstracts of qualitative research presented at the 1998 (n = 110) and 1999 (n = 114) British Sociological Association (BSA) Medical Sociology meetings, and attempted to locate those studies in databases or by contacting authors. We also appraised the quality of reporting in each abstract.

We found an overall publication rate for these qualitative studies of 44.2%. This is nearly identical to the publication rate for quantitative research. The quality of reporting of study methods and findings in the abstract was positively related to the likelihood of publication.

Qualitative research is as likely to remain unpublished as quantitative research. Moreover, non-publication appears to be related to the quality of reporting of methodological information in the original abstract, perhaps because this is a proxy for a study with clear objectives and clear findings. This suggests a mechanism by which "qualitative publication bias" might work: qualitative studies that do not show clear, or striking, or easily described findings may simply disappear from view. One implication of this is that, as with quantitative research, systematic reviews of qualitative studies may be biased if they rely only on published papers.