How does the Work Level Request Button in Vega select the edition for a hold?

Vega Discover

What logic does Vega Discover use when selecting which edition within a multi-edition work level-rollup will be used for the hold request?

Why Does Vega Need Special Hold Logic?

Vega Discover differs from PAC, Encore, and WebPAC in that editions of the same title rollup into one work. In PAC, Encore and WebPAC patrons must scan a long list of search result hits for every edition of the same title to locate an edition that has a copy available on the shelf or to select a specific edition with copies that they would like to request for hold.  This is a frustrating experience for the patron.  

With Vega's work level rollups a patron can select from 1 or a few rolled-up search results for the same title with combined editions and availability by location.  For patrons looking for a copy immediately available in the library work level rollups make it much simpler to find that material.  For patrons looking to place a request for a hold online: after selecting a format tab for the type of material they would like to receive, the work level hold button will select the best edition for them to quickly fulfill their hold.  This greatly reduces choice overload for patrons, and simplifies the hold process for the majority of patrons who do not care about the edition of a title and only want a copy in hand as soon as possible.  

Once a request for a specific edition is made in Vega, the ILS does the rest of the hold logic required to select a copy to fulfill the hold upon receiving the request.  This additional request logic is all configured in the ILS settings.

How Does Vega Select an Edition When I use the Work Level Hold Button?

Vega applies edition selection logic when a patron uses the work level hold button to attempt to choose an edition that will most quickly fulfill a hold for that specific patron.  Patrons are able to place holds on specific editions by opening the edition table and using the place hold button displayed for their desired edition.  The work level hold logic uses the following parameters to select the best edition for the patron:

1. Edition with most Available Copies at the Patron Pickup Location (or Home Location, see details below)
2. Edition with most Available Copies at other locations
3. Edition with Best Holds:Copies Ratio

Full Details of Logic Used

1. If there are copies available at the Patron's Pickup Location as selected in the Hold form, Vega selects the edition of that work that has the MOST copies available at the pickup location to fulfill the hold.
2. If there are no copies existing at the Patron's Pickup Location as selected in the Hold form, Vega looks at the Patron's Home Location and selects the edition with the most available copies at the Patron Home Location. 
3. If all existing copies at the Pickup Location and Home Location are currently unavailable, but there are available copies at other locations Vega chooses the edition with the most available copies overall. 
4. If all copies of the title are unavailable, Vega chooses the edition with the best Holds:Copies ratio to fulfill the hold.  
5. In all cases above, if two or more editions have the same amount of available copies, or the same holds:copies ratio, Vega chooses the newest of those editions to fulfill the hold. 

What about Volumed Materials?

Generally volumed materials such as serials have only one edition.  However, when materials with volumes have multiple editions Vega still applies our edition selection logic first, and then presents the Volumes or Items (depending on how your library does volume requests) for the selected edition to the patron so that they can request the desired volume or item for a hold.  

Examples of Holds:Copies Ratio selections: 

Example Work 1

Edition 1: no holds, 1 copy 0:1 (0/1) = 0

Edition 2: 2 holds, 2 copies 2:2 (2/2) = 1

Logic chooses Edition 1 because the single copy can be immediately trapped for a hold when it is returned, whereas Edition 2's two copies will be trapped for existing holds before the patron can get a copy.  The holds:copies ratio is lower for edition 1 0:1 (0/1) = 0 < 2:2 (2/2) = 1. 

Example Work 2

Edition 1: 8 holds, 5 copies 8:5 (8/5) = 1.6

Edition 2: 10 holds, 5 copies 10:5 (10/5) = 2

Logic chooses Edition 2 because the holds:copies ratio is lower.  8:5 (8/5) = 1.6 < 10:5 (10/5) = 2

Visual Examples of Vega Holds Logic: