Scatter and Decay: EJournal Usage Patterns
Carol Tenopir, UT SIS
Gayle Baker, UT Libraries
David Nicholas,University College London
Maximizing Library Investments Through
Better Data Gathering and Analysis:
Maxdata
MaxData Objectives



To compare different methods of data
collection
To develop a model that compares costs
and benefits to the library of collecting and
analyzing data from various methods
To help libraries make the best use of data
Survey Methods and Populations
Teams
Usage Data
Universities
Population
Format
Deep Log
(Ciber)
All OhioLink, Faculty &
4 Ohio
Students,
combined
Electronic
Library only
Surveys
UTK, 4 Ohio,
2 Australian
Faculty &
Students,
separate
Electronic
and Print,
Library and
Non-Library
Vendor
Reports
UTK
Faculty &
Students,
combined
Electronic
Library only
2 Findings for Today
1.
2.
Scatter
Decay
Scatter



To go in many directions
The relative dispersion of points on a
graph, especially with respect to a
mean value, or any curve used to
represent the points.
Reading varies by subject discipline
Average Number of Articles Read per year
by US University Faculty and Students by
subject disciplines (surveys/all readings)
450
434
369
400
350
300
242
239
251
250
200
177
173
Faculty
149
136
124
150
100
50
0
Medical/Health Social Science
Sciences
Engineering
Humanities
Student
Downloads by Subject (Sept – Nov 2005) - 4
Ohio universities
Hum
Med
4.7%
34.3%
Soc Sci
20.6%
Eng
Science
7.5%
32.9%
Number of downloads by subject (staff v student)
- Sept to Nov 2005, 4 Ohio universities
1200
1137
1000
800
752
600
Staff-Student
400
200
0
Staff
220
65
Med
134
72
Eng
Science
Student
Hum
Soc Sci
Ave Minutes/reading/University
Faculty Member (surveys)
43
45
40
35
30
25
36
35
37
24
20
15
10
5
0
Med
Science
Eng
Soc Sci
Hum
Average number of seconds per view by
subject Sept – Nov 2005 - 4 Ohio universities
150
135
124
124
109
100
107
50
0
Med
Science Eng Soc Sci Hum
UTenn COUNTER JR1 Usage
Data, Sep.-Nov. 2005
Full text downloads cumulated per
title, Sept – Nov, 2005 UTenn
Full text downloads cumulated per title,
Sept – Nov, 2005 - 4 Ohio Universities
100
80
%
60
40
20
0
00
50 0
0
45 0
0
40 0
0
35 0
0
30 0
0
25 0
0
20 0
0
15 0
0
10
0
50
0
Decay



the process of gradually becoming
inferior
a gradual decrease
Reading falls by age of articles
Decay of Article Readings by
U.S. University Faculty
Decay in article downloads (by year) –
Sept to Nov 2005 4 Ohio universities
30000
20000
10000
0
0
2
4
6
8
10
12
14
16
18
20

Nicholas, Huntington, Jamali and Tenopir.
Article Decay in the Digital Environment:
An Analysis of Usage of OhioLINK by
Date of Publication, Employing Deep Log
Methods, JOURNAL OF THE
AMERICAN SOCIETY FOR
INFORMATION SCIENCE AND
TECHNOLOGY, 57(13):1840–1851,
2006.
Decay of Article Readings by
Subject Discipline: U.S. Faculty
Decay in article downloads (by year) - Sept to
Nov 4 Ohio universities – by subject
8000
SUBJECT
6000
Med
4000
Science
Eng
2000
Soc Sci
Hum
0
0
2
4
6
8
10 12 14 16 18 20
Next Steps




Continue to analyze, compare, and
contrast various methods
Examine more possibilities of log
collection in libraries
Calculate time/cost of all methods
Compare benefits of all methods with
costs