Designing Collection Experiences: Availability

Designing Collection Experiences:
2. Availability
Roy Kenagy
rjkenagy@netins.net
www.whatwouldranganathando.org
September 17 & October 1, 2013
Waterloo Public Library

Exercise
What are some collection
performance measures?

“The most important figures that one needs
for management are unknown or
unknowable… but successful management
must nevertheless take account of them.”
W. Edwards Deming. Out of the Crisis.
Cambridge, Mass.: Massachusetts Institute
of Technology, Center for Advanced
Engineering Study, 1986, p. 121, crediting
Lloyd S. Nelson.

The mission of librarians is to help
create transformative meaning in the
lives of readers and the conversations
of communities.

The Many Collections Hypothesis

Charlie Robinson
Baltimore County
Public Library
“Give ‘em what they
want, when they
want it.”

Availability: Are the texts that the
reader would prefer to select
presented when the reader would
prefer to select them?

Reader Library
Texts
Collection
In
Use
Shelved
Collection
Other
Text
Experiences
Other
Library
Experiences

Rod Pierce. "Definition of Ratio." Math Is Fun. Ed.
Rod Pierce. August 24, 2013.
http://www.mathsisfun.com/definitions/ratio.html

1,500 items in use
8,500 items shelved
1. What is the ratio of
items in use to
items in the
collection?
2. What is the ratio of
items on the shelf
to items in the
collection?
10,000 items in the collection

Availability Surveys
Measuring reader satisfaction

Availability survey ratio:
just ask the readers…

Van House, Nancy A., Mary Jo
Lynch, Charles R. McClure, Douglas
L. Zweizig, and Eleanor Jo Rodger.
Output Measures for Public
Libraries: A Manual of Standardized
Procedures. 2nd ed. Chicago:
American Library Association, 1987.

“The principle categories of dissatisfaction”
Paul B. Kantor "Availability Analysis," Journal of
the American Society for Information Science 27,
no. 5 (September-October 1976) 311-19.
F=109
FrustrationSuccess

Exercise
What are some sources of library and
reader error in availability studies?

Library Error & Reader Error
Library Error Reader Error

Bill Price and David Jaffe.
The Best Service Is No
Service: How to Liberate
Your Customers From
Customer Service, Keep
Them Happy, and Control
Costs. San Francisco:
Jossey-Bass, 2008.

Unlike the graphic arts, drawing, or photography, unlike
tracings, the rhizome pertains to a map that must be
produced, constructed, a map that is always detachable,
connectable, reversible, modifiable, and has multiple
entranceways and exits and its own lines of flight. It is
tracings that must be put on the map, not the opposite.
Gilles Deleuze and Félix Guattari. A Thousand Plateaus:
Capitalism and Schizophrenia, translated and with a
forward by Brian Massumi. Capitalism and
Schizophrenia, 2. Minneapolis University of Minnesota
Press, 1987, p. 20.

Relative use
The relation between the holdings ratio
and circulation ratio of a rhizome. An
indicator that a rhizome may be over-
sized or under-sized.

Relative use
F. Wilfred Lancaster,. If You Want to Evaluate
Your Library . . . 2nd ed. Champaign, IL:
University of Illinois, Graduate School of Library
and Information Science, 1993.
Gregory R. Mostyn. "The Use of Supply-Demand
Equality in Evaluating Collection Adequacy,"
California Librarian 35 (April 1974) 16-23.

Collection
Holdings
Ratio
Circulation
Ratio
Relative Use
Youth .25 .50 2.00
Adult .75 .50 .67

Collection Holdings Circulation
Holdings
Ratio
Circulation
Ratio
Relative Use
Youth 8,000 19,500 0.24 0.35 1.4
Adult 20,000 21,000 0.61 0.37 0.6
Media 5,000 16,000 0.15 0.28 1.9
Total 33,000 56,500

Other applications of relative use
• Interlibrary loan
• Holds
• Missing or not returned
• Withdrawn for damage or wear

Brief Test Holdings Availability
White, Howard D. Brief Tests of
Collection Strength: A Methodology for
All Types of Libraries. Westport, CT
Greenwood, 1995.

Brief Test Holdings Availability

Rod Pierce. "How to Calculate the Mean
Value" Math Is Fun. Ed. Rod Pierce. April 21,
2013.
http://www.mathsisfun.com/mean.html

Rod Pierce. "Definition of Median" Math Is Fun. Ed. Rod
Pierce. Aug 23, 2013.
http://www.mathsisfun.com/definitions/median.html

Picture book holdings in Iowa libraries

The Language of the Levels
Conspectus
0. Out of scope
1. Minimal
2. Basic information
3. Instructional support
4. Research
5. Comprehensive
Not Conspectus
• Happiness
• Glee
• Eternal joy
• The cat’s pajamas

Takeaway from “Brief Tests”
holdings measure
Validate checklists by looking in a union
catalog (WorldCat, Iowa Locator, etc.) to find
the distribution of holdings for each title.
More holdings means a title that will appeal
to more readers.

1,500 items in use
8,500 items shelved

Snapshot: A snapshot is
a download of status
data about the items in a
collection at a specific
instant in time. Because
status data cycle slowly
over loan periods,
snapshots provide stable
indicators of long-term
relationships and trends.

Circulation Period Daily change
1 week 0.14
2 weeks 0.07
3 weeks 0.05
4 weeks 0.04

Exercise
Explain why it is misleading to use a Random
Availability snapshot of a collection as an
indicator of the availability that the reader
actually experiences.

0
0.93
0.95
0.65
0.47
0.89
0.94
0
0.94 0.95
0.40
0.27
0.57
0.82
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Collection Adult 500s Adult 900s Board Books DVDs Beginning
Readers
Adult Fiction
Random
Reader-Weighted
Comparison between random and reader-weighted availability
Data from Grimes Public Library, September 2004

Reader-Weighted Availability:
Sample from collection in use
Roger Edward Stelk and F. Wilfred Lancaster.
"The Use of Shelflist Samples in Studies of
Book Availability," Collection Management
13, no. 4 (1990) 19-24.

1,500 items in
use
8,500 items
shelved
Random
Sample
Reader-
Weighted
Sample
List of
all items
in use
with item
number
Snapshot

1,500
items in
use
8,500
items
shelved
1,500
items in
use
Reader-
Weighted
Availability
500 items
in use now
1,000 items
not in use now
June 15 sample July 30 sample
Reader-
Weighted
Sample

Collection development calendar

Shelf Sample

Sample from the collection in use
Data are from the Des Moines Public Library.

Sample from the collection in use
Collection
Collection in Use
No. of items in sample
Availability
% Change
Out
2/22/99
On Shelf
4/27/99
1999 1997
Young Adult 970 608 .63 n.a. n.a.
YS Nonfiction 2,611 2,069 .78 .69 9%
YS Fiction 1,148 902 .79 .77 2%
Picture Books 5,745 3,196 .56 .46 10%
J Paperbacks 1,008 616 .61 .46 15%
Audio discs 4,461 1,988 .45 .48 -3%

Estimates from Demand Tables
Philip M. Morse. "Demand for Library
Materials: An Exercise in Probability
Analysis," Collection
Management, 1, no. 3-4 (Fall-Winter
1976), 47-78.

Turnover
Turnover is the mean annual circulation per
item of a rhizome.

Use original circulations
if possible
For all calculations involving circulation, use
original circulations if possible, rather than
original circulations plus renewals.

1.
Collection
2.
Number
of Items
3.
Original
Circulation
4.
Turnover
5-6.
Loan
Period
7.
Demand
per item
Table
8.
Total
Demand
Picture Books 3,843 16,199 4.2 3 weeks
Board Books 407 2,536 6.2 3 weeks
Videos 1,127 10,949 9.7 1 week
DVDs 805 13,015 16.2 1 week
Audiobooks - tapes 1,005 2,327 2.3 3 weeks
Audiobooks - CDs 438 971 2.2 3 weeks
Exercise: Reader-Weighted Availability,
Estimate from Demand Tables:
Turnover, Demand Per Item, Total Demand

Core assumption: The mean amount
of time an item is out per checkout
is equal to the standard length of
loan for the item’s rhizome.
Readers visit the library on a regular
schedule that is in synch with the
library’s checkout periods.

Distribution of length of loans
Ames Public Library 1988-89

Mean length of loan, Ames
Public Library: 17.6 days
Add 3 days for reshelving: 21 days

Time since last arrival
Stanley J. Slote. Weeding Library
Collections: Library Weeding Methods. 4th
ed. Littleton, CO: Libraries Unlimited, 1997.

Time on shelf = 365 – 21 = 344
Time on shelf = 365 – 273 = 92

Turnover/Time between arrivals/
Annual Circulations:
Individual Items
Turnover
Time
between
arrivals
Weekly
circulation
Seat-of-the-
pants annual
circulation
1 344 1/52 = .0192 1
13 7 1 52

Mean demand increases
exponentially in relation to turnover.
Exponential increase: The rate of increase gets
higher as turnover gets higher (curves upward),
rather than staying the same (straight line).

0
5
10
15
20
25
30
35
40
45
50
0 2 4 6 8 10 12 14 16 18
Turnover
MeanDemandPerItem
4 weeks
< 1 week1 week2 weeks
3 weeks
Mean demand per item by turnover
For standard library loan periods – groups of items

Demand tables
I have built a demand table for each standard
length of loan. Use the table to look up the
turnover for a rhizome and the corresponding
mean demand per item. Round down if a
turnover is not listed.

1.
Collection
2.
Number
of Items
3.
Original
Circulation
4.
Turnover
5-6.
Loan
Period
7.
Demand
per item
Table
8.
Total
Demand
Picture Books 3,843 16,199 4.2 3 weeks 7.6
Board Books 407 2,536 6.2 3 weeks 15.8
Videos 1,127 10,949 9.7 1 week 19.2
DVDs 805 13,015 16.2 1 week 60.5
Audiobooks - tapes 1,005 2,327 2.3 3 weeks 3.1
Audiobooks - CDs 438 971 2.2 3 weeks 3.0

Estimate total demand for a rhizome
(total potential circulations)
Multiply the Demand per Item times
the Number of Items.

Total demand for a rhizome
(from table)

1.
Collection
2.
Number
of Items
3.
Original
Circulation
4.
Turnover
5-6.
Loan
Period
7.
Demand
per item
Table
8.
Total
Demand
Picture Books 3,843 16,199 4.2 3 weeks 7.6 29,207
Board Books 407 2,536 6.2 3 weeks 15.8 6,431
Videos 1,127 10,949 9.7 1 week 19.2 21,638
DVDs 805 13,015 16.2 1 week 60.5 48,703
Audiobooks - tapes 1,005 2,327 2.3 3 weeks 3.1 3,116
Audiobooks - CDs 438 971 2.2 3 weeks 3.0 1,314

Calculate Reader-Weighted
Availability
Divide Original Circulation by
Total Demand.

Reader-weighted availability
using table

1.
Collection
3.
Original
Circulation
8.
Total Demand
(above)
Reader-
Weighted
Availability
Picture Books 16,199 29,207 .55
Board Books 2,536 6,431 .39
Videos 10,949 21,638 .51
DVDs 13,015 48,703 .27
Audiobooks - tapes 2,327 3,116 .75
Audiobooks - CDs 971 1,314 .74
Reader-Weighted Availability,
Reader-Weighted Availability

Exercise
List the duplication practices that you
have used or are aware of.

Duplication Practices
• Number of holds
• Past experience with an
author or title – gut
feelings – gross
circulation
• Best seller lists – 2 copies
if it’s on the list
• Book to movie tie-ins
• High risk books
• Interlibrary loans as early
indicator
• Buzz
• Popular author list –
automatically yours
• Popular series – at least
as many as we bought of
the last volume
• Suggestions for purchase
– number of people
• How it’s used – popular
use/academic use
• Press runs

7-Day Median Arrival Time
Circulations
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Weeks

Random arrival times with circulation periods
2 3 5 3 2 2 3 4 3 1 2 2

Random arrivals are approximated
by the normal curve
S.D. = Standard Deviation

The Tool Crib Formula
Robert S. Grant. "Predicting the Need for Multiple
Copies of Books," Journal of Library Automation 4, no.
2 (June 1971) 64-71.
Leffler, William L. "A Statistical Method for Circulation
Analysis." College and Research Libraries 25
(November 1964): 488-490.

𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑜𝑝𝑖𝑒𝑠 = 1 +
𝐷𝑎𝑦𝑠 𝑖𝑛 𝑙𝑜𝑎𝑛 𝑝𝑒𝑟𝑖𝑜𝑑 × 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑐𝑖𝑟𝑐𝑢𝑙𝑎𝑡𝑖𝑜𝑛𝑠
𝐷𝑎𝑦𝑠 𝑖𝑛 𝑐𝑖𝑟𝑐𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑙𝑖𝑓𝑒

Each additional added copy results
in fewer additional circulations.

Duplication tables for one through
four week loan periods are
available at:
www.whatwouldranganathando.org

Always Available Lists
Brian Smith. "The Always (Almost
Always) Available Book System."
U*N*A*B*A*S*H*E*D Librarian, no. 5
(Fall 1972) 3.

Designing Collection Experiences: Availability

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