DOIs Should Not Link to Data In August of 2011, the National Academy of Science’s Board of Research Data and Information (BRDI) had a meeting on the topic of “Developing Data Attribution and Citation Practices and Standards”. As part of that meeting were various breakout groups to discuss issues that still remained regarding technical, scientific, and socio-cultural issues, the roles and actors that needed to be involved, and how to get additional feedback from the community. The technical breakout group decided that the majority of the technical problems with citing data revolved around establishing the identity of what it was that we were attempting to cite. As such, our recommendations were to push some of the work back onto the data publishers to tell us how scientists should cite their data (to avoid different disciplines applying different rules), establish ‘data landing pages’ to describe, document and link to the data, and to provide those pages with persistent identifiers such as a DOI. We present here some of the reasons that were discussed about why not to link directly to data, including: recalibration, reaccessioning and other data impermanence, setting context and providing links to documentation, and allowing selection of different packaging formats http://virtualsolar.org/ IN13B-1564 J.A. Hourclé NASA-GSFC (Wyle) joseph.a.hourcle@nasa.gov Data Impermanence: Recalibration / Versioning New processed forms of data create a slightly different problem from outright removal; as one form of the data is deprecated, a new form supersedes it Some projects will generate new calibrations of the data as the sensor degredation is better understood without a fixed release. Some data is released in near-real-time, with a reprocessing pass done after additional calibration tests are run. In the case of NASA’s Solar Dynamics Observatory’s (SDO) Atmospheric Imaging Assembly (AIA), data is available immediately after downlink, reprocessed 4 days later, then again 6 months later, each time improving the precision of the resultant data. Multiple calibrations of the same observation from SOHO/EIT For long-lived projects, the data is not fixed until after the data gathering concludes. The joint NASA/ESA Solar and Heliophysics Observatory (SOHO) was launched on December 2, 1995, with instruments that have been collecting data for almost 18 years and have not generated a ‘final data product’. Once these better calibrations are available, the older data is obsolete and, in some fields, discarded. Due to a lack of data citation standards, there is no easy way to identify which versions may have been used as part of the scientific record and should be maintaned long-term. Keeping all editions of the data is not cost-effective, and so only the raw data and ‘final data product’ are archived for the long-term. If people attempt to link to data that has been superseded, the archive has a few choices: Return the original data (or the replacement) We don’t know why someone was following the link: are they doing new research or trying to validate older work? Replacements may be suitable if your identifiers are for the observations (as is done in some Active Archives), but typically DOIs are used for objects with a fixed form and this would not be expected. Redirect to the replacement. This will give a clue that a replacement has been made, but most browsers and automated user agents will redirect without any indication that they did so. Return a message explaining what’s happened. Automated agents may not realize what’s happening. If served as a success (HTTP 200), they may assume it’s the data requested. If served as common redirections (HTTP 301 to 307), most user agents will redirect without displaying the message. HTTP 300 (Multiple Choices) without a Location header is your best option. You need a response is over 1024 bytes to avoid browser rewriting. Data Impermanence: Deaccessioning / Removal If data isn’t actively used by the designated