Monday, November 10, 2014

New TREC Blog

In case you missed it, OTREC is now TREC. We have a new website, which includes a researcher blog. I have a post there about our peer-to-peer carsharing research.

Monday, July 21, 2014

Five findings from a quick analysis of bicycle research


People often think that because I'm a professor, I "have the summer off." That's far from reality. I may not be teaching classes during the summer, but I am still managing the research center I direct, reviewing draft dissertations, conducting research, writing, going to meetings, speaking at conferences, and applying for research grants. It was during the latter activity that I got distracted (which is more likely to happen in the summer) with analyzing metrics of research on bicycling. I've been reading a bit lately about research metrics, including this analysis of citations that concluded that 1% of "scientists" produce a large share of all the research, and Tom Sanchez's analysis of citations of research by urban planning faculty. Like any good researcher, I'm quick to find faults with the methods and analysis. But like any good data geek, I'm also easily lulled into crunching some numbers myself. So even after I got the answer I needed for my proposal after a few clicks, I couldn't help myself from exploring the data more—and sharing what I found.

My method was simple. I conducted a search in Web of Science using the topic bicycl* (to include bicycle, bicycling, etc.). I limited the search to the categories of transportation, transportation science technology, social science interdisciplinary, and urban studies. This was to minimize research that uses the term "bicycle" for other meanings. It does, however, likely exclude some medical research, e.g. on the health effects of bicycle seats, as well some social science or historical research. I also limited the findings to articles, proceedings, and book chapters published in English.

Here are my five quick findings. (And, please excuse the poor table formatting. Posting on a blog is new for me.)

1. The amount of published research has boomed in the past five years.
As shown below, little research was published prior to 1990. This is somewhat consistent with federal funding for bicycle and pedestrian infrastructure in the U.S. and shifts in policy prompted, in part, by ISTEA (passed in 1991). The amount increased in the early 2000s, but really takes off starting in about 2007. If I had the time I would compare this to the volume of all publications regardless of topic and perhaps some other topics, e.g. asphalt. By the way, there are 44 publications from 2014 in the Web of Science database so far.



 2. Follow me to where the research happens (she says, somewhat kiddingly)


My alma maters UC Berkeley and UC Davis, followed by my current home, Portland State University, top the list of the organizations of the authors of research published in the past ten years (2004-2013). More seriously, the list reveals some concentration of activity. Those three universities represent one out of every 10 publications. Seven universities produced 20% of the publications. I will note that my third alma mater, UCLA, doesn't even show up in the top 50. I will also admit when I include all years in the analysis, Portland State drops to 5th. Moreover, I'm not implying any causality.


Table 1. 2004-2013 Publications, by Organization (limited to organizations with 6 or more)
Rank
Organization
# 

(n=655)
Cumulative %
1
UNIV CALIF BERKELEY
26
4.0
2
UNIV CALIF DAVIS
20
7.0
3
PORTLAND STATE UNIV
19
9.9
4
UNIV TEXAS AUSTIN
17
12.5
5
UNIV N CAROLINA
17
15.1
6
SOUTHEAST UNIV
15
17.4
7
MCGILL UNIV
15
19.7
8
RUTGERS STATE UNIV
14
21.8
9
QUEENSLAND UNIV TECHNOL
12
23.7
10
UNIV MINNESOTA
11
25.3
11
UNIV COLORADO
11
27.0
12
DELFT UNIV TECHNOL
11
28.7
13
TONGJI UNIV
10
30.2
14
UNIV SYDNEY
9
31.6
15
UNIV BRITISH COLUMBIA
9
33.0
16
INST TRANSPORT ECON
9
34.3
17
UNIV WISCONSIN
8
35.6
18
UNIV WASHINGTON
8
36.8
19
UNIV CALGARY
7
37.9
20
OHIO STATE UNIV
7
38.9
21
MONASH UNIV
7
40.0
22
ARIZONA STATE UNIV
7
41.1
23
UNIV UTRECHT
6
42.0
24
UNIV TORONTO
6
42.9
25
UNIV TOKYO
6
43.8
26
UNIV TEXAS
6
44.7
27
UNIV NEW S WALES
6
45.6
28
UNIV MARYLAND
6
46.6
29
UNIV GRONINGEN
6
47.5
30
UNIV CENT FLORIDA
6
48.4
31
TEXAS A M UNIV
6
49.3
32
BEIJING JIAOTONG UNIV
6
50.2







 3. Research funding is not concentrated, though China is supporting a lot of it


Not all Web of Science entries include the funding source for the research, but it's becoming more common to do so. The top two funders identified are from China, followed by two university transportation centers in the U.S. – UCTC housed at UC Berkeley and OTREC housed at Portland State University. A number of agencies funded five of the publications, including FHWA and the National Cooperative Highway Research Program (NCHRP), which is supported largely through state DOT research funds. Also note that the search reveals a common problem with databases using entries from multiple sources and people. There are two more OTREC sources towards the bottom of the list that are entered with a slightly different title. I didn't spend any time cleaning up the data.


Table 2. Top funding agencies for research published 2004-2013
Funding Agencies
#
% of 655
NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA
12
1.832
NATIONAL BASIC RESEARCH PROGRAM OF CHINA
6
0.916
UNIVERSITY OF CALIFORNIA TRANSPORTATION CENTER
5
0.763
OREGON TRANSPORTATION RESEARCH AND EDUCATION CONSORTIUM
5
0.763
NCHRP
5
0.763
NATURAL SCIENCES AND ENGINEERING RESEARCH COUNCIL OF CANADA
5
0.763
NATIONAL SCIENCE FOUNDATION
5
0.763
MINETA TRANSPORTATION INSTITUTE
5
0.763
FHWA
5
0.763
U S DEPARTMENT OF TRANSPORTATION
4
0.611
CALIFORNIA DEPARTMENT OF TRANSPORTATION
4
0.611
TONGJI UNIVERSITY
3
0.458
SOUTHERN CALIFORNIA ASSOCIATION OF GOVERNMENTS
3
0.458
ROBERT WOOD JOHNSON FOUNDATION
3
0.458
NATURAL SCIENCE FOUNDATION OF CHINA
3
0.458
CANADIAN INSTITUTES OF HEALTH RESEARCH
3
0.458
CANADIAN FOUNDATION FOR INNOVATION
3
0.458
AUSTRALIAN RESEARCH COUNCIL
3
0.458
TRANSLINK
2
0.305
TEXAS DEPARTMENT OF TRANSPORTATION
2
0.305
TENNESSEE DEPARTMENT OF TRANSPORTATION
2
0.305
QUEENSLAND DEPARTMENT OF HEALTH
2
0.305
OREGON TRANSPORTATION RESEARCH AND EDUCATION CONSORTIUM OTREC
2
0.305
NATIONAL NATURE SCIENCE FOUNDATION OF CHINA
2
0.305
NATIONAL KEY BASIC RESEARCH PROGRAM OF CHINA
2
0.305
NATIONAL KEY BASIC RESEARCH PROGRAM NKBRP OF CHINA
2
0.305
MINISTRY OF CONSTRUCTION
2
0.305
MICHIGAN DEPARTMENT OF TRANSPORTATION
2
0.305
MICHAEL SMITH FOUNDATION FOR HEALTH RESEARCH
2
0.305
KOREA GOVERNMENT MEST
2
0.305
FUNDAMENTAL RESEARCH FUNDS FOR THE CENTRAL UNIVERSITIES
2
0.305
FONDS QUEBECOIS DE LA RECHERCHE SUR LA NATURE ET LES TECHNOLOGIES
2
0.305
ENVIRONMENTAL PROTECTION AGENCY
2
0.305
CITY OF AUSTIN
2
0.305
BEIJING HUAIROU INTELLIGENT TRANSPORTATION MANAGEMENT DEMONSTRATION
2
0.305

 
4. Thank you, Transportation Research Board
The largest single outlet for publishing this research is the Transportation Research Board, through its journal, Transportation Research Record (Table 3). More than one-third of the publications appeared there (when you include the earlier versions of the title, such as PEDESTRIANS AND BICYCLES DEVELOPING COUNTRIES, etc. Each issue of the journal has a substantive subtitle and in earlier years these were entered in the Web of Science as the journal title.) The sources also reveal that safety is a major topic, with 121 articles published in Accident Analysis and Prevention in the past 10 years.

Table 3. 2004-2013 Publications, by Source (limited to sources with 5 or more)
Source Titles
#
% of 655
TRANSPORTATION RESEARCH RECORD
211
32.2
ACCIDENT ANALYSIS AND PREVENTION
121
18.5
TRANSPORTATION RESEARCH PART A POLICY AND PRACTICE
27
4.1
TRANSPORT POLICY
25
3.8
JOURNAL OF TRANSPORT GEOGRAPHY
25
3.8
TRANSPORTATION
22
3.4
TRANSPORTATION RESEARCH PART D TRANSPORT AND ENVIRONMENT
21
3.2
TRAFFIC INJURY PREVENTION
20
3.1
ITE JOURNAL INSTITUTE OF TRANSPORTATION ENGINEERS
16
2.4
TRANSPORTATION RESEARCH PART F 

TRAFFIC PSYCHOLOGY AND BEHAVIOUR
11
1.7
JOURNAL OF SAFETY RESEARCH
11
1.7
TRANSPORT AND SUSTAINABILITY
9
1.4
INTERNATIONAL JOURNAL OF SUSTAINABLE TRANSPORTATION
9
1.4
CYCLING AND SUSTAINABILITY
9
1.4
JOURNAL OF TRANSPORTATION ENGINEERING ASCE
8
1.2
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
8
1.2
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL

 ENGINEERS PART D JOURNAL OF AUTOMOBILE ENGINEERING
7
1.1
PEDESTRIANS AND BICYCLES DEVELOPING COUNTRIES
7
1.1
INTERNATIONAL JOURNAL OF AUTOMOTIVE TECHNOLOGY
7
1.1
BICYCLES AND PEDESTRIANS DEVELOPING COUNTRIES 2005
7
1.1
URBAN STUDIES
5
0.8
URBAN AND INDUSTRIAL ENVIRONMENTS
5
0.8
TRANSPORTATION RESEARCH PART B METHODOLOGICAL
5
0.8
JOURNAL OF URBAN PLANNING AND DEVELOPMENT ASCE
5
0.8
JOURNAL OF THE AMERICAN PLANNING ASSOCIATION
5
0.8
CITY CYCLING
5
0.8

 5. This is meant as a quick snapshot, not a deep, perfectly accurate analysis


As with any data collection and analysis that occurs in less than 4 hours, this isn't perfect. Yes, I know Web of Science doesn't have everything and is biased toward older, larger, established sources. I use Google Scholar quite a bit, but the analytics on Web of Science are more thorough, and Google Scholar has a lot of overlapping sources (e.g. a final report, conference presentation, and journal article all covering the same research product). And, there is a lot of research that doesn't show up in either source. As noted above, I didn't clean the data in any way and appropriate sources were missed and inappropriate ones (where bicycle means something else) undoubtedly included. I'm sure there are other caveats.