PID Guide methodology
The PID Guide was produced by the Digital Heritage Network’s Persistent Identifiers project. Working with experts from Delft University of Technology (for DataCite DOI), SURFsara (Handle) and the National Library of the Netherlands (URN:NBN), a list was produced of 25 subjects relevant to choosing a PID system. For each subject, the three PID systems were rated on a five-point scale, ranging from “This system doesn’t support this/isn’t suited to this” (1) to “This system fully supports this/is fully suited to this” (5). The rating was determined collectively by the experts representing the different PID systems.
An example: one subject concerns the use of PIDs for scientific citation. Every PID system supports this, but DataCite DOI is specifically tailored to it, and was acknowledged as such. For this reason, Handle and URN:NBN were given a rating of 3, and DataCite DOI a rating of 5.
Next, the 25 subjects were converted into statements. Users of the PID Guide can indicate their agreement or disagreement with each statement on another five-point scale, ranging from “I fully disagree” (1) to “I fully agree” (5). The statement in the example above was: “My PIDs are primarily intended for citation and reference by researchers.”
In most cases, the percentile degree of correspondence between the user’s reply and the expert rating for each PID system is calculated using a distance formula:
correspondence = ( 5 – | expert rating – user reply | ) / 5 * 100
In some cases a larger-than formula is used instead. On the subject of costs, for example. if an organisation has a large budget and indicates as much, a (virtually) free PID system might be unreasonably ranked as less suitable. The PID Guide averts this problem as follows: whenever a user reply has a higher value than the expert rating, correspondence is set to 100%. If not, the distance formula applies.
The PID Guide was improved over a number of iterations using both expert and user input, and has been integrated into the National Coalition for Digital Durability (NCDD)’s website. The NCDD partners aim to continuously improve their services and are interested in your responses, findings and feedback. Please contact us at firstname.lastname@example.org, email@example.com or firstname.lastname@example.org.
The PID Guide may be used and distributed according to the CC0 license guidelines. Please note that although the PID Guide is based on general knowledge about PID systems, it was developed with the Dutch situation in mind.