ADAPTED
PHYSICAL ACTIVITY QUARTERLY, 2001, 18, 434-450
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© 2001 Human Kinetics Publishers, Inc.
O’Connor, French, Sherrill, and Babcock
Scholarly Productivity in Adapted
Physical Activity Pedagogy:
A Bibliometric Analysis
John O’Connor
Southern Illinois University Edwardsville
Ron French and Claudine Sherrill
Texas Woman’s University
Garth Babcock
Eastern Washington University
The purpose was to determine whether publications pertaining to adapted physical activity (APA) pedagogy in the core serials from 1988 to 1998 adhere to
library science laws. A bibliometric analysis was conducted on 770 articles in
259 serials selected from 4,130 serials initially identified in four databases
(Article First, ERIC, Medline, Sport Discus). Results indicated that 1,720 authors have constructed the early APA pedagogy literature. Of these, only 11
contributed four or more articles. The scatter of APA pedagogy literature over
four zones, with 4, 15, 64, and 176 journals in the zones, respectively, supports Bradford’s law of scattering. Price’s law was not supported because most
authors contributed only one article. Most pedagogy articles (n = 184) were
published in Adapted Physical Activity Quarterly, Medicine and Science in
Sport and Exercise, Physician and Sports Medicine, and Palaestra. Graduate
education should include exposure to bibliometrics and collaboration with library and information science specialists.
Within adapted physical activity, scholars have noted the need for increased
quantity and improved quality of research papers (Reid, 2000; Reid & Broadhead,
1995; Sherrill & O’Connor, 1999; Sutlive & Ulrich, 1998). In this paper, adapted
physical activity refers to the profession and scholarly discipline recognized by
the National Association for Physical Education in Higher Education (NAPEHE)
as one of the nine knowledge areas that comprise the field of exercise and sport
John O’Connor is with the Department of Kinesiology at Southern Illinois University, Edwardsville, Campus Box 1126, Edwardsville, IL 62026. E-mail: <[email protected]>.
Ron French and Claudine Sherrill are with the Department of Kinesiology at Texas Woman’s
Univeristy, Denton, TX. Garth Babcock is with the Physical Education, Health, and Recreation Department at Eastern Washington Univeristy, Cheney, WA.
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Bibliometrics and Adapted Physical Activity
435
science (Massengale & Swanson, 1997), also known as kinesiology. Adapted physical activity is also the term of preference internationally for interdisciplinary and
crossdisciplinary theory and practice related to the life span physical activity of
individuals with psychomotor limitations and/or needs (Doll-Tepper, Dahms, Doll,
& von Selzam, 1990; Sherrill & DePauw, 1997). Adapted physical activity theory
and practice pertain to physical education, recreation, and sport that is adapted at
the individual or program level (Porretta, Nesbitt, & Labanowich, 1993; Sherrill,
1998) as well as to psychomotor therapy, an active profession in Europe (Reid &
Broadhead, 1995).
Both individuals and professional organizations have addressed the issue of
what knowledge should comprise adapted physical activity and what kinds of research should be conducted to produce this knowledge (e.g., Broadhead, 1984;
Doll-Tepper et al., 1990; Doll-Tepper & DePauw, 1996; Jansma & Surburg, 1995;
Kelly & Gansneder, 1998; National Consortium for Physical Education and Recreation for Individuals with Disabilities, NCPERID, 1995). Beliefs about what
adapted physical activity is and the topics that comprise its knowledge base are
documented in the professional literature. However, the help of library and information scientists is often needed to locate sources and to understand the developing knowledge base.
The development of a scholarly discipline with clearly defined subdisciplines is clearly dependent on the creation of a knowledge base through the publication of theoretical articles, review papers, reports of original research, and works
that describe and/or explain applications (Broadhead, 1984; Reid & Ulrich, 2001;
Sherrill & O’Connor, 1999). Unlike some scholarly disciplines that publish their
work primarily in two or three journals, adapted physical activity is represented in
a variety of journals and conference proceedings (i.e., the emerging content of our
field is widely scattered). This “scatter phenomenon,” as well as the crossdisciplinary
nature of adapted physical activity, increases the difficulty of monitoring the quantity and quality of knowledge. It also complicates decision making of scholars
with regard to which journals to purchase and of faculty with regard to which
journals should be introduced to students.
Bibliometrics
Important to the advancement of a discipline is the systematic evaluation by self
and others of the journals that publish its scholarly products, of the impact of these
journals, and of the most productive scholars within the profession (O’Connor,
Sherrill, & French, 2001; Reid & Broadhead, 1995; Reid & Ulrich, 2001). To
achieve these goals, collaboration with library and information science professionals in bibliometrics is helpful. Bibliometrics is the name given by library and
information science to the study of patterns of publication and characteristics of
literature (Diodato, 1994; Hawkins, 1977). Bibliometrics is used to examine scholarly productivity as classified by author, journal, discipline, affiliation, etc. A
bibliometric researcher is able to identify the attributes that make a specific body
of literature unique from other collections.
There are three basic features of bibliometric research (Narin, Olivastro, &
Stevens, 1994). Activity measurement (the focus of our study) refers to counts of
publications and authors that describe scholarly activity in a selected discipline.
Impact indication determines the number of times an article is cited in subsequent
O’Connor, French, Sherrill, and Babcock
436
articles (e.g., Reid & Ulrich, 2001; White, 1990). Whether a citation is supportive
or derogatory is irrelevant. The fact that one article is cited more frequently than
another makes its contribution to the literature, whether positive or negative, more
significant than the less cited article (Meho & Sonnenwald, 2000). Relationship
examination is the study of links between articles, journals, researchers, and institutions (Lawani, 1981; Narin et al., 1994). For example, Baughman and Goldman
(1999) review literature that shows a strong relationship between faculty publications and university rankings.
Bibliometrics dates back to the 1900s (Cole & Eales, 1917) and is governed
by several laws and principles (e.g., Bradford’s law of scattering and Price’s law
relating to patterns of citation). Following is a brief description of the laws addressed in this study.
Bradford’s Law of Scattering
Bradford’s law of scattering is a measure of serial productivity (i.e., the relative
contributions of serials to the literature on a particular topic). A serial is any publication comprised of a number of separate and successive parts with a constant
title (e.g., journals or proceedings of periodic meetings) that is published for consecutive issues at a regular interval over an infinite time period (Nicholas & Ritchie, 1978).
Concerning serial productivity (the relative contributions of serials to the
literature on a particular topic), Bradford (1948) explained that (a) most journals
contribute only one article on a specific topic—the other articles are not relevant
to the subject of the search; (b) few journals contribute an average of 5 to 10
articles each; and (c) very few journals contribute a large number of articles each
(Lawani, 1981; Rao, 1998). This distribution (scattering) of articles was reported
first by Bradford (1934) and later by others (Basu, 1992; Egghe, 1990; Kendall,
1960) to take a very regular pattern. This consistent pattern holds for nearly any
body of literature, regardless of discipline. Bradford (1948) named this phenomenon the law of scattering. The term scattering describes the widespread distribution of articles among serials. The most productive serials (journals, periodicals,
or proceedings) are those that are, in some way, most important to the professional
discipline. The extent of this importance is determined without regard to the age or
date of the articles and their citations (Bradford, 1934, 1948). In Bradford’s words
(1934):
The whole range of periodicals thus acts as a family of successive generations of diminishing kinship, each generation being greater in number than
the preceding, and each constituent of a generation producing inversely according to its degree of remoteness. (p. 96)
In other words, Bradford found that articles scatter among journals in a fashion that is highly predictable and deducible. Bradford’s law of scattering enables
scholars to (a) identify serials that comprise the nucleus (core) periodicals of a
subject, (b) determine the number of serial titles required to cover a certain fraction of the total serial population of a subject, and (c) ascertain if an allegedly
complete bibliography is in fact complete.
Illustrative of the application of Bradford’s law in physical education literature is a study by Loy (1979) in which 100 North American-based authors, who
contributed 658 publications to the sociology of sport literature, were analyzed.
Bibliometrics and Adapted Physical Activity
437
Using Brookes’ (1977) formulation of Bradford’s law, Loy reported that the productivity patterns of the 100 authors produced a perfect Bradford distribution (a
graphic depiction of the scatter of articles among serials), comprising 10 core authors. Each of these authors had 15 or more publications, which together accounted
for over 40% of the published work. Loy concluded that the sociology of sport
literature supported Bradford’s law. The findings of Loy’s study have serious implications for scholarship in physical education generally and sport sociology specifically. Loy reported that sociology of sport, as an academic specialty in North
America, lacked a critical mass of active researchers. Of the total number of sport
sociologists identified (N = 160), only 100 had two or more publications (Loy,
1979). Sport sociology is recognized by NAPEHE (Massengale & Swanson, 1997)
as one of the nine knowledge areas that comprise the field of exercise science and
sport, and thus Loy’s study is particularly related to ours.
Price’s Law
Price’s law is one approach to studying the impact factor (i.e., the number of times
an article is cited in subsequent articles). The importance of the impact factor in
adapted physical activity has recently been discussed by Reid and Ulrich (2001).
Price stated that success breeds success in increasing author productivity;
this has come to be known as Price’s law (Price, 1980b). According to Price’s law,
half of the literature on a topic will be contributed by the square root of the total
number of authors publishing on that topic (Diodato, 1994). Price’s law is an attempt to describe the “total world network of scientific papers (Price, 1965, p.
510). Price wrote extensively on both author productivity and impact.
According to Price, 35% of all papers are never cited, while 49% of papers
are cited only once. This leaves 1% of all papers to be cited six or more times.
Regardless of the frequency of citing, each year, 10% of all papers “die,” never to
be cited again. This birth, life, and death of papers is an important concept in the
endeavor to understand the productivity rates of authors and journals and the interrelated phenomenon of citation.
Purpose of Study
The purpose of this study was to determine whether publications pertaining to
pedagogy published in the serials that encompass adapted physical activity content from 1988 to 1998 support Bradford’s law of scattering and Price’s law of
success breeds success. It was hypothesized that the adapted physical activity pedagogy serials for the selected time period of 1988 to 1998 would display characteristics consistent with Bradford’s law and Price’s law. In this study, serials were
journals (periodicals) and commercially published proceedings of conferences and
symposia of the International Federation of Adapted Physical Activity (IFAPA).
Parts of both journals and proceedings were referred to as articles throughout this
study.
The inclusive dates 1988 to 1998 were chosen for the present study based on
the criteria of practicality and similarity to other studies (Vishwanatham, 1998).
The year 1988 was selected as the time starting date because it allowed scholars
ample time to discover and begin publishing in Adapted Physical Activity Quarterly and Palaestra, the two major journals in adapted physical activity, both of
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O’Connor, French, Sherrill, and Babcock
which began publication in 1984. The 1980s have been identified as the decade
when adapted physical activity leaders first began to consider the field to be an
emerging scholarly discipline (Sherrill & DePauw, 1997).
Delimiting Our Research to Pedagogy
Despite its relative youth as a profession and scholarly discipline, adapted physical activity has developed many subspecializations. These subspecializations have
been recognized in professional literature (Reid & Broadhead, 1995), by organizations (Massengale & Swanson, 1997; NCPERID, 1995), and by textbooks (e.g.,
Sherrill, 1998). We decided to delimit our analysis of literature to pedagogy in that
it appears to have the largest critical mass of content. Following is the rationale for
our belief that pedagogy, broadly defined, is the largest content area of adapted
physical activity.
Pedagogy is the term used to encompass the overlapping areas of teaching
and coaching, curriculum, teacher education, and teachers’ lives and careers (Bain,
1996; Silverman & Ennis, 1996). The term is accepted internationally (Pieron,
Cheffers, & Barrette, 1990) as well as by NAPEHE, which recently specified pedagogy as one of the nine subdisciplines comprising the field of exercise and sport
science (Massengale & Swanson, 1997). Content related to education practices,
programs, policies, goals, and outcomes thus can be considered to be pedagogy.
Documentary analysis of the content of articles offers insight into the relative importance of various subspecializations or orientations. Reid and Broadhead
(1995), in a documentary analysis of the 290 articles published in Adapted Physical Activity Quarterly during its first 10 years of existence, classified articles under 12 scientific orientations (i.e., subspecializations): pedagogy, assessment/
classifications, integration, biomechanics, physiology, medicine/rehabilitation, sport
psychology, motor learning/control, motor development, research issues, legislation/professional organizations, and history. These orientations were not defined,
but the authors proposed that they might be organized into three major categories:
educational, biological, or motor behavior. Education was defined as “an appropriate label for pedagogy, legislation, professional organizations, assessment, classification, and integration” (Reid & Broadhead, 1995, p. 105). Papers on education
accounted for 40% of the articles in APAQ during its first 10 years, while the
biological and motor behavior categories accounted for 25% and 24%, respectively.
Documentary analyses of Palaestra and Clinical Kinesiology are not available. However, these journals are designed to appeal primarily to practitioners and
contain mainly application articles that relate to teaching, coaching, or service
delivery. Overall, considering the journals most frequently associated with adapted
physical activity, the largest percentage appear to relate in some way to teaching
and coaching, curriculum, teacher education, and teachers’ lives and careers.
NCPERID has been the professional organization most active in identifying
the subspecializations of adapted physical activity. NCPERID (1995), after approximately 3 years of research involving 385 professionals representing 40 states,
identified specific content that adapted physical education teachers should know.
This content was organized and published as 15 standards, now widely known as
the Adapted Physical Education National Standards (APENS) and used as the basis for a nationwide volunteer adapted physical education certification examination (Kelly & Gansneder, 1998). Of the 15 standards, four pertained specifically to
Bibliometrics and Adapted Physical Activity
439
pedagogy (unique attributes of learners, curriculum theory and development, instructional design and planning, and teaching). Numerous other standards (e.g.,
assessment, program evaluation, consultation and staff development, continuing
education) might be classified by some experts as pedagogy.
Textbooks traditionally present their content by topic or subspecialization.
Among textbook authors who make direct reference to pedagogy, Sherrill (1998)
organized her textbook into three parts, with Part 2 (10 chapters) entitled “Assessment and Pedagogy for Specific Goals.” In this text, assessment and pedagogy are
interwoven, based on the concept that assessment should be continuous and should
drive everything that occurs in a teaching or coaching setting. Sherrill believes
that assessment can be conceptualized as either an independent topic or as a subcomponent of pedagogy.
Method
Pilot Study
The pilot study included decision making with respect to (a) selection of experts,
(b) definition of adapted physical activity pedagogy and physical education, (c)
selection of keywords and databases, and (d) validity and objectivity of decisions.
Experts used in the pilot study were consulted throughout the main study.
Selection of Experts. Library and information science and adapted physical activity experts assisted us in the design of the study and in specific decision
making with respect to databases, keywords, and serials to be included in the search.
Library and information science experts met the criteria of (a) doctoral and subsequent research on Bradford and Price and (b) 10 or more years as research librarians in a university setting. Adapted physical activity pedagogy experts met the
criteria of (a) at least 5 publications concerning adapted physical activity pedagogy in the last 5 years and (b) 10 or more years of experience teaching adapted
physical activity professional preparation courses at the university level.
Definitions of Adapted Physical Activity Pedagogy and Physical Education. Before we could begin this study, it was necessary to operationally define adapted physical activity pedagogy and to establish they key words to be used
in searches. Based on the generic definitions of Bain (1996) and Silverman and
Ennis (1996) and on the research underlying APENS (NCPERID, 1995), we chose
to define adapted physical activity pedagogy as the body of knowledge encompassed by four NCPERID standards: (a) teaching, (b) instructional design and planning, (c) curriculum theory and development, and (d) unique attributes of learners.
We then refined this definition as follows: Adapted physical education pedagogy
is school- or community-based curricular and/or teaching (instructional) processes
related to physical activity for individuals with disabilities. Physical education
was defined as curriculum and instruction related to assessing and improving physical and motor fitness; fundamental motor skills and patterns; and skills in aquatics,
dance, individual and group games, and sports. In this definition, we accepted the
basic premise of Sherrill (1998) that assessment and teaching are interwoven in
adapted physical education pedagogy.
Selection of Keywords. The keywords came from three sources: (a) APENS,
specifically the standards on curriculum theory and development, instructional
design and planning, teaching, and unique attributes of learners (NCPERID, 1995);
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(b) Educational Resources Information Center (ERIC); and (c) SportDiscus. We
selected ERIC and SportDiscus based upon advice from our library and information science experts and on our data-based research (O’Connor et al., 2001). Terms
used in the keyword search were pedagogy, physical education, and adapted physical
education. The search of the three databases resulted in 126 terms. Disability terms,
selected from disabilities covered in APENS and from those in the selected database thesauruses, were also used in the search procedure. The final disability term
list contained 66 terms. The list of terms used in the search procedures may be
obtained from the first author.
Selection of Databases. To determine which databases to use for this study,
we conducted searches within Article First, Educational Resources Information
Center (ERIC), SportDiscus, Medline, Education Abstracts, OT Bibliography Systems, and Health RefCtr. These databases were selected based on the recommendations of our library and information science experts. The four databases that
generated the largest number of hits for the selected keywords were used in this
study: Article First, ERIC, Medline, and SportDiscus. The protocol used to select
these databases was consistent with the methodology of Reid and Prupas (1998).
Validity and Objectivity of Decisions. Validity of the search terms was based
on the use of terms from APENS, which has been validated by adapted physical
activity professionals (NCPERID, 1995) and from the four database thesauruses.
Further support for content validity was established by submitting the search terms
for review to three experts in adapted physical activity pedagogy. Three experts
and the principal investigator independently judged (yes or no) whether articles
met the inclusion criteria (see below). During this decision-making process, each
article was individually reviewed for adherence to the inclusion criteria.
Criteria Used for Selecting Serials
1. Content must contain teaching suggestions or processes related to physical education for an individual with a disability and/or information on (a) health or
safety that would impact physical education services, (b) unique attributes of learners
in a physical activity setting, (c) benefits of physical education programming for
an individual with a disability, or (d) performance in different school-based exercise and physical activity settings for individuals with disabilities.
2. Documents must be written in English.
3. Documents must be written by one or more identified individuals. Documents produced by organizations or institutions were not eligible.
Objectivity of the search process was established through use of all of the
terms (n = 126) identified in the pilot study plus the disability terms (n = 66).
Excluding terms would have resulted in a potential bias and decreased the objectivity of the study.
Testing for Bradford’s Law of Scattering
To address the purpose of the study, we performed an analysis for the fit of
Bradford’s law of scattering. This involved ranking the serials and testing the ranking
for the presence of Bradford zones. Bradford zones are groupings depicted graphically with approximately equal numbers of articles. Zones typically display
Bibliometrics and Adapted Physical Activity
441
decreasing productivity, in that greater numbers of authors or serials are required
to maintain the nearly equivalent numbers of articles.
Article and Serial Productivity Ranking. The issues of every serial (i.e.,
journals and proceedings) were examined for the presence of articles that met the
selection criteria, and a single tally mark was made when a document was identified. This count yielded 259 serials when duplications in the articles were eliminated. Individual issue tallies for a particular serial were added together for yearly
totals; yearly totals were added together for the total number of articles located in
a given serial during the 11-year research period. This sum was considered the
article productivity indicator for each serial.
Serial Productivity Ranking. The 259 serials were then ranked according
to their respective article productivity levels, from the most productive serial to
the least productive serial. The most productive serial was ranked number 1. The
second most productive serial was ranked number 2, and so forth. The least productive serial was assigned the highest number.
Examining for Presence of Bradford’s Scattering. The ranked serials were
then examined for the presence of a Bradford distribution pattern (i.e., the number
and composition of zones). The steps taken in this procedure were based on previous studies involving the use of the Bradford’s law of scattering (e.g., Bradford,
1934; Lawani, 1981):
1. First, we randomly determined the number of zones (e.g., 7, 6, 5, 4) that
we believed would be present in the Bradford distribution. This number was used
to divide the total number of articles (N = 770) into zones comprised of an approximately equal number of articles. This process was guided by Bradford’s rule
that within the nucleus (i.e. the first zone), the sum of the articles of the most
productive serials should be divisible approximately evenly into the total productivity score. We repeated the process of randomly selecting a number of zones,
dividing the total number of articles into the number of articles in the nucleus
zone, and examining the resultant integer until we found the division that yielded
the smallest number of zones. The determinant factor in this process was the discovery of that number of zones which, following division into the total number of
articles, yielded an integer value closest to a whole number (i.e., 4.16 is closer to a
whole number than 7.34). Bradford’s law of scattering required that the fewest
number of possible zones be used where each zone holds an approximately equal
number of articles (Bradford, 1948).
2. Following determination of the Bradford zones, the ratio of the number of
serials in each zone to its preceding zone was calculated in order to identify the
Bradford constant (n) for the distribution. According to Bradford (1934, 1948), if
periodicals contributing to a subject are ranked and then grouped in such a way
that each group contributes the same number of articles, the number of periodicals
in each group will increase geometrically (Lawani, 1981). The literature of each
discipline tends to manifest its own Bradford distribution.
3. The Bradford distribution for adapted physical activity pedagogy was subjected to several tests of conformity. To test whether the data displayed a Bradford
distribution, Wallace’s (1985) tests for a minimal nucleus and plot of cumulative
articles were used. To test the goodness of fit obtained by the application of
Bradford’s law of scattering, a Kolmogorov-Smirnov Test (K-S test) was used
(Chongde & Zhe, 1998). The K-S test measures the degree of agreement between
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O’Connor, French, Sherrill, and Babcock
the distribution of a set of sample values and a theoretical distribution (Siegel &
Castellan, 1988).
Testing for Price’s Law
From the 770 publications identified through the Bradford distribution, a list of
authors was generated. Every author for each article or proceedings was included
in the list. Authors were listed without regard for position within the article byline. Authors who contributed more than one article were counted once.
Based on Price’s methodology (1980a, 1980b), the total number of publications, 770, was divided by two (n = 385). The square root of the total number of
authors (N = 1,720) contributing articles to the adapted physical activity pedagogy
literature was 41.47. This process revealed that 42 authors should have been required to contribute 385 articles on adapted physical activity pedagogy. This figure was compared to the obtained value from the Bradford distribution (329 authors
were required to generate the 187 articles in the nucleus) to determine the relevance of Price’s law for adapted physical activity pedagogy.
Results
The pilot study computer search resulted in 4,130 articles and proceedings across
the four databases. The results of this search were narrowed to 801 articles, using
the criteria stipulated in Table 1. When the overlap between databases was eliminated by removing duplicated articles, the final number of articles was 770. The
database with the greatest number of articles related to adapted physical activity
pedagogy was Sport Discus (n = 637). ERIC and Article First included 287 and
234 articles, respectively. The database with the smallest number of articles was
Medline (n = 35).
Bradford Distribution
Examination of the Bradford distribution revealed that the adapted physical activity pedagogy literature is best divided into four zones (see Figure 1). The first, or
nucleus zone, contained 186 articles distributed among four serials. The three succeeding zones had Bradford constants of 3.75, 4.27, and 3.59. A Bradford constant
is obtained by dividing the number of serials in a zone by the number of serials in
the previous zone. So every zone except the nucleus zone has a Bradford constant.
The Bradford constant of the distribution is the mean of these different Bradford
constants. The second zone was made up of 192 articles in 15 serials and a Bradford
constant of 3.75. The third zone was made up of 195 articles in 64 serials with a
Bradford constant of 4.27. The final zone was made up of 197 articles in 176
serials with a Bradford constant of 2.75. For adapted physical activity pedagogy
literature, an average Bradford constant of 3.59 was obtained. The size of this
constant is not meaningful outside of purely theoretical discussions. The meaningfulness of this analysis lies in the fact that the literature did display a pattern of
decreasing productivity within the established zones in accordance with Bradford’s
law of scattering (Bradford, 1934).
The first test of conformity of the data to Bradford’s law of scattering required application of a formula for determining the minimum size of a bibliography
Bibliometrics and Adapted Physical Activity
443
Figure 1 — Graphic representing Bradford distribution.
possessing the properties of a Bradford distribution (Wallace, 1985). This test of
conformity of the data is an examination of the goodness of fit of the data to a
theoretical Bradford distribution. Whether the data fit the theoretical distribution
is determined through visual inspection of the slope and curve of the graph. The
formula is A/m > z/2, where A/m = the number of articles in the minimal nucleus,
and z = the number of journals in the total distribution that each contribute only
one article (N = 195). For this study, the formula was 186 articles (articles in minimal nucleus) > 97.5.
Because, for the adapted physical activity pedagogy serials, 195 serials each
contributed one article, to demonstrate the properties of a Bradford distribution,
the minimal nucleus must contain at least 97.5 articles. The number of articles in
our nucleus zone met the criteria suggested by Wallace (1985). The obtained number of articles (N = 186) was greater than the minimal number (n = 97.5) derived
from the formula. Meeting this criterion supports the applicability of Bradford’s
law of scattering to adapted physical activity pedagogy literature.
The second test of conformity of the bibliography to Bradford’s law of scattering produced a graph with an initial curve followed by a linear portion and a
finishing section that contained the Groos droop (see Figure 2). The figure is a
graphic representation of the number of articles (vertical axis) plotted against the
logarithm of the ranks of the serials (horizontal axis). The slight droop at the end
of the curve is generally interpreted as a higher concentration of articles than expected in the most productive serials (Diodato, 1994). The presence of the initial
curve, linear portion, and Groos droop suggest that the adapted physical activity
pedagogy literature fits Bradford’s law of scattering.
A third test for the conformity of the data to Bradford’s law of scattering was
performed using a Kruskal-Wallis test (Chongde & Zhe, 1998). The number of
O’Connor, French, Sherrill, and Babcock
444
—
Figure 2 — Representation of the Bradford Distribution for Physical Actvity Pedagogy Literature.
articles in each zone was entered into a Kruskal-Wallis test to determine if the four
zones differed significantly on the number articles per zone. The Kruskal-Wallis
test indicated that the number of articles per quadrant (186, 192, 195, 197) was not
significantly different, c2 = 3, df = 3, p = .392, across the quadrants. This finding
confirmed that the articles were distributed into approximately equivalent groups.
A Kruskal-Wallis test was then performed to determine if the number of
serials per quadrant was significantly different. Across the four quadrants, the number of serials per quadrant (4, 15, 64, 176) was significantly different, c2 = 154.45,
df = 3, p = .0001. This finding also confirmed that the adapted physical activity
pedagogy literature displays characteristics of a Bradford distribution.
Four statistical tests thus indicated that the findings of our study supported
the Bradford law. When the Bradford distribution of our data were verified, we
identified the serials located in the nucleus and three succeeding zones (see Table
1). The 16 most productive serials are listed in Table 1. The authors of the articles
in the journals of the nucleus (Adapted Physical Activity Quarterly, Medicine and
Science in Sport and Exercise, Physician and Sportsmedicine, and Palaestra) were
counted (N = 416 authors). When duplicate authorship was eliminated, 329 authors contributed one or more articles to the nucleus cluster. The total number of
authors who contributed to the adapted physical activity pedagogy knowledge base
was 1,720.
Price’s Law
According to Price’s law, some number of writers in a field that is equal to the
square root of the total number of authors will account for about half of the total
publications in that field (Diodato, 1994). Testing of Price’s law required determining the square root for the 1,720 authors identified in this study and comparing
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445
Table 1 The Most Productive Serials in Adapted Physical Activity Pedagogy,
1988-1998
Serial
Number of articles
Nucleus (Zone 1, all journals)
Adapted Physical Activity Quarterly
Medicine and Science in Sport and Exercise
Physician and Sportsmedicine
Palaestra
Zone 2 (All Journals)
Sports Medicine
The Fourth International Symposium of Asian Society for Adapted
Physical Activity and Exercise: Theory and Practice of Adapted
Physical Activity and Exercise (1996). Asian Society for Adapted
Physical Activity and Exercise (ED.).
Archives of Physical Medicine and Rehabilitation
Clinical Kinesiology
Journal of Physical Education, Recreation, and Dance
Adapted Physical Activity: An Interdisciplinary Approach Proceedings of the 7th International Symposium (1990).
Doll-Tepper, G., Dahms, C., Doll, B., & von Selzam, H. (Eds.)
Brazilian International Journal of Adapted Physical Education Research
Journal of Autism and Developmental Disorders
Journal of Visual Impairment and Blindness
Pediatric Exercise Science
Perceptual and Motor Skills
British Journal of Physical Education
Zone 3 (Illustrative Journals)
British Journal of Sports Medicine
Journal of Applied Behavior Analysis
Teaching Exceptional Children
Zone 4 (Illustrative Journals)
Sport Psychologist
Sport Supplement
Sports Exercise and Injury
82
49
33
23
21
20
18
17
15
13
12
12
12
12
12
10
5
4
4
1
1
1
Note. Productive was defined as the number of articles related to pedagogy published by the
serial (journal, proceedings) in the time period defined by the study.
this value with 50% of 770, the total number of publications. The square root value
was 42, and 50% of 770 publications was 385. According to Price’s law, only 42
authors should have been required to generate 385 publications. Findings revealed,
however, that 329 authors contributed to the four serials in the nucleus, yielding
187 articles.
Of the authors who contributed to serials in the nucleus zone, 11 were identified as contributing 4 or more articles over 11 years and thus as being more
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productive than the other scholars. These authors contributed from 4 to 7 articles
for a total of 51 articles with a mean of 4.64 (– .92) articles. To match this level of
productivity required the combined productivity of the next 23 authors. However,
combining these two groups (11 most productive authors and 23 next most productive authors) does not begin to approach the criterion level of productivity required for Price’s law (9 articles per author). This finding does not support the
applicability of Price’s law to adapted physical activity pedagogy literature.
Discussion
Bradford’s Law
The hypothesis regarding Bradford’s law of scattering was accepted. The pedagogy literature displayed a regular pattern of scatter when the serials were placed
in monotonically decreasing order of productivity. The slope and pattern of the
graphical depiction of the data were also in keeping with Bradford’s law of scattering (Wallace, 1985).
The Bradford constant (M = 3.59) obtained for this study was larger than
those reported by others (e.g., Galloway, 1977; Lamb, 1971; Wallace, 1985). This
finding should not be considered good or bad; rather it is a reflection of the parameters of the search (Ingwersen & Christensen, 1997). The four databases used in
the present investigation increased the likelihood of thorough and complete coverage of the literature (O’Connor et al., 2001). In addition, search terms developed
from APENS and the thesauruses of the four databases insured good coverage of
pedagogy knowledge. Collaboration with experts in library and information science, as well as in adapted physical activity, provided validity for the search. Overall,
the adequacy and appropriateness of the parameters of our search are supported by
the combination of the diverse sources for search term development and validation
of the search terms through the database thesauruses and experts.
Some problems did occur in that the adapted physical activity experts, in the
final stages of the study, noted that the computer searches had failed to identify
some pedagogy articles. This problem was traced to the divers ways that authors
enter the keywords or descriptors for articles when they are published and included in the databases. Essentially what we did was use a source (APENS) developed by adapted physical activity professionals as representative of our knowledge
base. The problem occurred when we used the APENS terms in databases that
were maintained by library and information science personnel who are not familiar with our profession, adapted physical activity. This process led to some inconsistencies and to the exclusion of a few authors who should have been identified in
the search. We believe that this problem occurs frequently when adapted physical
activity scholars conduct computer searches for any purpose, and we recommend
more collaboration with library and information science specialists.
A delimitation of our research was to rely heavily on APENS and adapted
physical activity experts supportive of APENS pedagogy terminology. Future research is needed that relies on other sources (e.g., textbooks, focus group discussion) and/or combinations of APENS and other sources. For optimal monitoring
and quality control of our rapidly growing or changing knowledge bases, frequent
bibliometric research is needed.
Bibliometrics and Adapted Physical Activity
447
The Bradford distribution is impacted by the age and maturity of the subdiscipline it is employed to study. The “best” fit for a Bradford distribution occurs
when a field has matured (Garg, Sharma, & Sharma, 1993). During the process of
maturation, the core serials of a field stabilize. This stabilization represents a settling of the serials into regular patterns of publication that serve an established
audience of readers and researchers (Garg et al., 1993). The diversity of research
and literature presented within the serials studied supports the conclusion that professionals within adapted physical activity pedagogy are still engaged in exploring
boundaries. This is in agreement with the views of scholars who have identified
adapted physical activity as a maturing field (Reid, 2000; Sherrill & DePauw, 1997).
Although the Bradford distribution best describes mature fields, it has also
been used to examine the literature of young, developing professions (Shearer,
Burnham, Wall, & Turnbull, 1995). Occupational therapy and physical therapy
scholars have utilized a Bradford distribution to explore potential overlaps and
redundancies in their knowledge bases for the purpose of streamlining professional development schools. Shearer et al. (1995) reported that the 1,200 references they examined displayed both overlap and clear areas of distinction between
occupational therapy and physical therapy. These findings had implications for curriculum planners in eliminating dual coverage and strengthening areas of weakness.
Utilization of Bradford’s distribution to study adapted physical activity pedagogy has two major applications. One application relates to serials appearing in
the first quadrant or nucleus of the Bradford distribution. These serials contain
articles that tend to be more readable than serials appearing in succeeding quadrants (Galloway, 1977). This finding may have application for professionals seeking to educate undergraduate students, parents, and laypersons about adapted
physical activity. Use of materials identified as being easier to read may increase
the comprehension of individuals lacking the training to understand technical explanations. Increases in comprehension may lead to more informed decisions.
Second, serials appearing in the nucleus (Adapted Physical Activity Quarterly, Medicine and Science in Sport and Exercise, Physician and Sportsmedicine,
Palaestra) tend to contain articles by those individuals who are the most prolific
and highest quality authors. The quality of publication is often an indicator of the
frequency that an author will be cited. Identifying individuals whose articles are
contained in the nucleus would, according to Lamb (1971), provide young scholars with models of individuals who publish frequently and with high quality.
Price’s Law
The hypothesis regarding Price’s law (success breeds success) was not supported
by our findings. Most authors contributed only one article during their career. Only
11 authors published 4 or more articles, indicating that little follow up and replication was occurring. This finding has a direct relationship on citing practices because ideally, prolific authors cite their previous work as they extend the knowledge
base in a specific area (Reid & Ulrich, 2001).
Price (1980a) reported that a paper needs to have approximately 14 repeated
citings before it begins to generate new citings each year. It is possible because
adapted physical activity pedagogy is a young discipline that the critical threshold
of citations has not been reached to start generating new citations. This finding
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O’Connor, French, Sherrill, and Babcock
would be important in that it would support the suggestion that adapted physical
activity is not a mature field but rather an emerging field of study. Further, this
finding would indicate a need for authors to form networks of citing to insure that
quality research does not prematurely disappear into the archives before its full
impact can be felt.
Our findings indicating that most authors contribute only one article is similar to that of Reid and Broadhead (1995) who stated that over the first 10 years of
APAQ publications, only 9 authors published 6 or more articles, another 16 authors
published 4 to 5 articles, and 20 authors published 3 articles (i.e., only 45 out of
386 authors contributed more than 3 articles).
Conclusion
In conclusion, the application of Bradford’s law of scattering and Price’s law that
success breeds success provides insight into scholarly productivity within the pedagogy subspecialization of adapted physical activity. Our findings support Bradford’s
law in that 770 articles were scattered among 259 serials in a predictable pattern,
allowing us to identify the four journals that contribute the most to the knowledge
base. Our findings did not provide support for Price’s law in that 329 authors were
responsible for 25% of the literature, whereas 42 authors were predicted to account for 50% of the literature. Further research, in close collaboration with library and information scientists, is needed. Graduate education in adapted physical
activity should include exposure to bibliometrics and specific training in citation
skills and in critical thinking about the impact of specific articles and journals.
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