We adopted an old Yale extent formula for containers a long time ago and have stuck by it; we don’t usually measure folders in terms of linear feet. If a collection is really small, we might count the number of folders the total collection extent. We might also use the # of folders as the extent for a series/subseries if it is less than 0.2 linear feet (1/2 size document box.)
1 records storage box = 1 linear foot or 1.25 cubic feet
1 document/manuscript box = 0.4 linear feet
1 ˝ size document/manuscript box = 0.2 linear feet
1 oversized flat box = 0.3 linear feet (we rarely use varied sizes of flat boxes)
1 oversized folder = 0.1 linear feet (not really accurate, but we’re stickin’ to it!)
It’s hard to mix items and containers and make it all make sense according to linear feet. For AV extent in a mixed materials collection, we generally use the measurement of the container that actually houses the audiovisual item/items.
However, I could see a “mixed extent” also working, such as “0.4 linear feet; 2 sound recordings.”
For us, consistency is key because we barcode all of our containers and have extent measurements attached to those barcode items. This is how we’re able to do statistical reports on our holdings.
Barbara D. Aikens
Chief, Collections Processing | Archives of American Art, Smithsonian Institution
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From: Encoded Archival Description List [mailto:[log in to unmask]] On Behalf Of Nathan Tallman
Sent: Thursday, March 28, 2013 1:16 PM
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Subject: Extent Measurements
Apologies for cross posting!
Does anybody have a handy chart or reference for what they use to estimate extent measurements? I'm thinking about when a collection comes in of 3 audiocassettes or if a collection is 7 Hollinger boxes and 4 DVDs. I've seen estimates for folders (ranging from 0.01 to 0.04+ linear feet), but never a comprehensive list.
Something that gives a measurement per unit. For example:
audiocassette 0.02 linear feet
record carton 1.00 linear feet
folder 0.02 linear feet
CD-ROM 0.01 linear feet