An analysis of key indicators of reproducibility in radiology

BACKGROUND: Given the central role of radiology in patient care, it is important that radiological research is grounded in reproducible science. It is unclear whether there is a lack of reproducibility or transparency in radiologic research. PURPOSE: To analyze published radiology literature for the presence or lack of key indicators of reproducibility. METHODS: This cross-sectional retrospective study was performed by conducting a search of the National Library of Medicine (NLM) for publications contained within journals in the field of radiology. Our inclusion criteria were being MEDLINE indexed, written in English, and published from January 1, 2014, to December 31, 2018. We randomly sampled 300 publications for this study. A pilot-tested Google form was used to record information from the publications regarding indicators of reproducibility. Following peer-review, we extracted data from an additional 200 publications in an attempt to reproduce our initial results. The additional 200 publications were selected from the list of initially randomized publications. RESULTS: Our initial search returned 295,543 records, from which 300 were randomly selected for analysis. Of these 300 records, 294 met inclusion criteria and 6 did not. Among the empirical publications, 5.6% (11/195, [3.0–8.3]) contained a data availability statement, 0.51% (1/195) provided clear documented raw data, 12.0% (23/191, [8.4–15.7]) provided a materials availability statement, 0% provided analysis scripts, 4.1% (8/195, [1.9–6.3]) provided a pre-registration statement, 2.1% (4/195, [0.4–3.7]) provided a protocol statement, and 3.6% (7/195, [1.5–5.7]) were pre-registered. The validation study of the 5 key indicators of reproducibility—availability of data, materials, protocols, analysis scripts, and pre-registration—resulted in 2 indicators (availability of protocols and analysis scripts) being reproduced, as they fell within the 95% confidence intervals for the proportions from the original sample. However, materials’ availability and pre-registration proportions from the validation sample were lower than what was found in the original sample. CONCLUSION: Our findings demonstrate key indicators of reproducibility are missing in the field of radiology. Thus, the ability to reproduce studies contained in radiology publications may be problematic and may have potential clinical implications.