Jeremy Kenyon, Nancy Sprague, and Edward Flathers have published "The Journal Article as a Means to Share Data: a Content Analysis of Supplementary Materials from Two Disciplines" in the Journal of Librarianship and Scholarly Communication.
Here's an excerpt:
INTRODUCTION The practice of publishing supplementary materials with journal articles is becoming increasingly prevalent across the sciences. We sought to understand better the content of these materials by investigating the differences between the supplementary materials published by authors in the geosciences and plant sciences. METHODS We conducted a random stratified sampling of four articles from each of 30 journals published in 2013. In total, we examined 297 supplementary data files for a range of different factors. RESULTS We identified many similarities between the practices of authors in the two fields, including the formats used (Word documents, Excel spreadsheets, PDFs) and the small size of the files. There were differences identified in the content of the supplementary materials: the geology materials contained more maps and machine-readable data; the plant science materials included much more tabular data and multimedia content. DISCUSSION Our results suggest that the data shared through supplementary files in these fields may not lend itself to reuse. Code and related scripts are not often shared, nor is much 'raw' data. Instead, the files often contain summary data, modified for human reading and use. CONCLUSION Given these and other differences, our results suggest implications for publishers, librarians, and authors, and may require shifts in behavior if effective data sharing is to be realized.