Immediate vs. Delayed Access

Bo-Christer Björk is quite right. The Elsevier study's arbitrary (and somewhat self-serving) 6-category classification system (each of whose categories is curiously labelled a "publishing system") leaves much to be desired.

It is not just what Elsevier called "Gold Open Access" that was Gold Open Access, but also what they called "Subsidised." The difference is merely that what they called Gold was publishing-fee-based Gold and what they called subsidized was subsidy-based Gold:

1. Gold Open Access
2. Hybrid
3. Subsidised
4. Open Archives
5. Green Open Access: Pre-print versions
6. Green Open Access: Accepted Author Manuscript versions
Elsevier also neglected to mention that "Subsidised" did not necessarily mean subsidized either: There are also subscription-based journals that make their online versions free immediately upon publication; hence they are likewise Gold OA journals.

What Elsevier called "Open Archives" is also not what it sounds like: It seems to be Delayed Access articles, accessible only after a publisher embargo, either on the publisher's website or in another central website, such as PubMed Central, where publishers also deposit, sometimes immediately, sometimes after an embargo.

The two Green Open Access categories are also ambiguous.The pre-print versions are (correctly) described as pre-refereeing drafts (but it would take a lot closer analysis to determine whether the pre-prints differ from the refereed version. It is easy to determine whether they were posted before the official publication date but far from easy to determine whether they were posted before refereeing. (The date of the letter of acceptance of the refereed draft is often one that only the author and the editor know -- though it is in some cases printed in the journal: did Elsevier look at that too?)

The post-refereeing author's drafts are presumably what they are described as being, but it is not clear by what criteria Elsevier distinguished them from pre-refeeeing drafts (except when they were in an institutional repository and specifically tagged as unrefereed).

So, as Bo-Christer points out, there are many methodological questions about the data without whose answers their meaningfulness and interpretability is limited. I would say that the timing issue is perhaps the most important one. And to sort things out I would like to propose a different system of classification:

Open Access (OA): The term OA should be reserved for immediate OA, regardless whether it is provided by the publisher (Gold) or the author (Green). A reasonable error-margin for OA should be within 3 months or less from publication date. Anything longer begins to overlap with publisher embargoes (of 6, 12, 24 months or longer).

Delayed Access (DA): The term DA should be used for delays of more than 6 months. And besides the usefulness of separately counting 6, 12, and 24 month DA, DA should also be analyzed as a continuous variable, reckoned in months starting from the date of publication (including negative delays, when authors post the refereed draft during the interval from acceptance date to publication date. The unrefereed preprint, however, should not be mixed into this; it should be treated as a separate point of comparison.

So there is Gold OA (immediate), Green OA (immediate), Gold DA and Green DA (measured by 6-month intervals as well as continuously in months.

If a separate distinction is sought within Gold, then fee-based Gold, subsidy-based Gold and subscription-based Gold can be compared, for both OA and DA. The locus of deposit of the Gold is not relevant, but the fact that it was done by the publisher rather than the author (or the author's assigns) is extremely relevant.

For Green OA and DA it is also important to compare locus of deposit (institutional vs. institution-external). See mandates below.

In all cases independence and redundancy should uniformly be controlled: Whenever a positive "hit" is made in any category, it has to be checked whether there are any instances of the same paper in other categories. Otherwise the data are not mutually exclusive.

If desired, all the above can be further subdivided in terms of Gratis (free online access) and Libre (free online access plus re-use rights) OA and DA.

Tracking Gold has the advantage of having clear unambiguous timing (except if the publication date differs from the date the journal actually appears) and of being exhaustively searchable without having to sample or check (if one has an index of the Gold OA and DA journals).

Tracking Green is much harder, but it must be done, because the fight for OA is rapidly becoming the fight against embargoes. That's why Green OA should be reserved for immediate access. It is almost certain that within the next few years most journals will become Gold DA (with an embargo of 12 months). Hence 12 months is the figure to beat, and Green DA after 18 months will not be of much use at all.

And the best way to push for immediate Green OA, is to upgrade all Green mandates to require immediate institutional deposit, irrespective of how long an embargo the mandate allows on DA. Requiring immediate deposit does not guarantee immediate OA, but it guarantees immediate Almost-OA, mediated by the repository's automated copy-request Button, requiring only one click from the requestor and one click from the author.

The immediate-deposit requirement plus the Button not only fits all OA mandates (no matter how they handle embargoes of copyright), making it possible for all institutions and funders to adopt it universally, but it also delivers the greatest amount of immediate access for 100% of deposits: immediate Green OA for X% plus (100-X)% Button-mediated Almost OA. And this, in turn will increase the universal demand for immediacy to the point where publisher embargoes will no longer be able to plug the flood-gates and the research community will have the 100% immediate Green OA it should have had ever since the creation of the web made it possible by making it possible to free the genie from the bottle.

Stevan Harnad