Understanding what proportion of usage relies on PTA

[roger...@uwindsor.ca]

Hello everyone,

I am trying to better interpret the usage attributed to post-termination access (PTA) in the forecasts. 

As I understand it, Unsub uses the PTA date ranges that we supply, along with an pattern of usage by article-age derived from a study of aggregated journal usage, in order to estimate how frequently people will use the backfiles.

In the forecast that I have been working with, 39% of the estimated usage (over the next 5 years) will be through the PTA backfiles. This is with 0 subscribed journals. If I begin to add subscribed journals, for a la cart purchasing, the PTA number remains at 39%.

I am wondering if the PTA number should decrease as the number of subscriptions increase, as folks can begin to use the subscriptions to access the journals? How do you contextualize the PTA access when comparing to the other access methods: OA, subscription, unknown / ILL?

Thanks for your time :) 

Regards, Roger

Roger Reka

Leddy Library, University of Windsor

[Heather Piwowar]

Hi Roger, 

Yes this is a good question.  

Some kinds of requests can be fulfilled by multiple paths, like an OA article you also have PTA access to, or an OA article you also subscribe to, or as you say an article you could get by either PTA or subscription. 

In order to simplify thinking about this, we've assigned each article request only one fulfillment path in the bar chart.  We've assigned request fulfillment path via a priority order, with the top one first:

• OA
• PTA
• subscription
• ILL
• Unknown

So if we forecast an article could be fulfilled via OA, we count it in that segment even if it could also be fulfilled via one of the lower priority paths.

We recognize that often people will get things via subscription if the library has a subscription even if it is green OA or also in your PTA, but we show it this way partly to make it clear only what a subscription is buying you -- it is often less than people think, when they aren't accounting for PTA and open access.

Anyway, that is why the PTA fulfillment percentage doesn't go down when you model subscribing to new journals.

Hope that helps explain what is going on?

Heather

 

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Heather Piwowar, cofounder

OurResearch: tools to make scholarly research more open, connected, and reusable

follow at @researchremix, @OurResearch_org, @unpaywall, and @unsub_org

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