This is the accepted version of the following article:[Yoda, Tatsuro. "The effect of collaborative relationship between medical doctors and engineers on the
productivity of developing medical devices." R&D Management 46.S1 (2016): 193-206.]
which has been published in final form at [http://onlinelibrary.wiley.com/doi/10.1111/radm.12131/full]

1

The effect of collaborative relationship between medical doctors
and engineers on the productivity of developing medical devices
Keywords: medical devices, medical doctors, collaboration, medical engineering, bibliometric analysis

Tatsuro Yoda, Ph.D.
Senior Analyst. Institute for Future Engineering
Tomiokabashi Building, 2-6-11 Fukagawa, Koto-ku, Tokyo 135-8473 JAPANE-mail: t.yoda@ifeng.or.jp

Abstract
Previous research on medical devices R&D paid close attention to the role of medical doctors as usersof medical devices, but they did not examine enough the interdisciplinary collaboration between
medical doctors and engineers as a team of developing a medical device. In this paper, I looked at theeffect of collaborative relationship between medical doctors and engineers on the productivity of thedevelopment based on interviews on R&D of artificial retina and bibliometric analysis on R&D of
cochlear implant.
In the interviews with medical doctors and engineers involved in R&D of artificial retina in the U.S.,
Germany and Japan, we found that medical doctors and engineers perceive that the collaboration is oneof the key factors to the success in inventing and developing medical devices, but that the goodcollaborative relationship is difficult to maintain. Next we examined such collaboration quantitatively
by conducting bibliometric analysis of research articles and patents related to the development of2

cochlear implant, and found the important role played by medical doctors and their collaboration withengineers when designing and improving the medical device, and that more collaboration between
medical doctors and engineers is seen in the more productive R&D group.
Considering those findings, development of a medical device needs not only the “user-led” forces of
medical doctors but also close interdisciplinary collaboration between medical doctors and engineers asa team. For such collaborative team effort to succeed, absorptive capacity of both sides and proximity
between them are important, while there are barriers between a medical doctor and an engineer
including cognitive, organizational, social, and institutional factors. To overcome those barriers,
experiences of cooperation, education, geographic proximity, good leadership or member’s personality
can promote some elements of proximity to compensate for lack or shortage of other elements ofproximity.

3

1. Introduction
Not all developments of major medical devices necessitated the involvement of medical doctors, but
significant proportion of development involved the efforts of both medical doctors and engineers.1
Blume (2009), who studied R&D of cochlear implant, observed that “a technically inclined physician
or surgeon, dissatisfied with an existing technique, begins to sketch out what a better one might be.”The role of medical doctors in R&D on medical devices has been studied mainly as one type of “userled” innovation (von Hippel, 1988), that is, the development needs the involvement of medical doctors
as knowledgeable users of the device. Those studies pointed out the importance of users as sources ofinnovation when users see more economic rents in innovation than manufactures. Some of thosestudies did case studies on R&D of medical devices and focused on the role of medical doctor as a userof medical devices. One characteristic of medical doctors as users is that they have very advanced
knowledge in the fields of medical sciences.
Shaw (1985) argued that any equipment that is to be introduced into clinical use needs clinicalassessment and trial, and the “state of the art” clinical and diagnostic knowledge resides in clinicians as
1

Medical device is an instrument, and so on “intended for use in the diagnosis of disease or otherconditions, or in the cure, mitigation, treatment, or prevention of disease” (US Food and Drug
Administration (FDA),
http://www.fda.gov/medicaldevices/deviceregulationandguidance/overview/classifyyourdevice/ucm051
512.htm, accessed in November 16, 2014). And see Saltzman (2009, Table 12.2) on examples ofbiomedical inventions.

4

a user. Lettl et al. (2006) pointed out that medical doctors who contribute to innovation as users havehigh motivation for discovering a new solution, have a variety of competencies as a set, and play a roleas an entrepreneur. Other studies that analyzed the importance of medical doctors as a user are Shahand Robinson (2006), Chatterji et al. (2008) and Lüthje (2003). Significant factors that motivate
physicians as a user to develop medical devices other than seeing more economic rents are peer
approval, patient approval, and “instinct of workmanship” (Fuchs, 1998).
But I argue that what is needed for a successful development of a medical device would be not only the
involvement of medical doctors as a user but also close interdisciplinary collaboration between a
medical doctor as a user of the device and an engineer as a designer of the device. It is necessary toshare knowledge, skills and techniques, especially when the development needs a technologicalbreakthrough (Katz and Martin, 1997). As Saltzman (2009) explained in his textbook on biomedical
engineering, engineers, scientists and physicians work closely as a team when inventing, designing, andbuilding a medical device.
What previous research on R&D of medical devices did not explore enough was when, in what degreeand how medical doctors and engineers collaborate when developing medical devices and its effect on
R&D productivity. In this paper, I intend to examine the importance and hurdles of the collaborative
relationship between medical doctors and engineers (abbreviated as “CME” hereafter) for developmentof medical device based on interviews on R&D of artificial retina, and then examine CME’s effect on
the productivity of developing a medical device based on bibliometric analysis on R&D of cochlear
implant.
5

I do not deny that there are many studies that analyzed R&D collaboration between firms, between
firms and universities, or that analyzed collaboration among researchers based on their informal
networks. Those studies pointed out the importance of the links between firms and universities or
involvement by firms and government labs in research joint ventures. In addition, there are studies
conducted on “impact of interfirm networks on performance” or “the effects of interfirm networks onpatenting, access to information, and the generation of novel ideas.” Firms can use interorganizational
networks effectively as a means to “pool or exchange resources and jointly develop new ideas andskills,” especially when the scientific or technological progress is rapid and it is difficult to have all thenecessary knowledge (Powell and Grodal 2006).
In addition to the studies on inter-organizational collaboration, there are studies that looked at the roleof informal ties or knowledge sharing between persons belonging to different firms. There are studies
that looked at the network of scientists, often termed “invisible colleges.” It is an “informal network of
researchers who form around a common problem or paradigm.” There are many studies that tried tounderstand how such structure of scientific communities affects the expansion of knowledge. (Powell
and Grodal 2006, p.73)
What I intend to do in this study relating to collaborative efforts of developing a medical device isdifferent from those studies on inter-organizational collaboration or collaboration among researchers
based on informal network relations. Rather it relates to the recently emerging research field of thestudies on science of team science or team R&D. Science on team science’s focus is more on to explore
under what conditions interdisciplinary type of collaboration succeeds in a research team and to6

understand how to overcome the inter- or trans-disciplinary barriers among team members in order toachieve their common goal. Those studies try to understand and enhance “the processes and outcomes
associated with team-based initiatives that are undertaken to promote cross-disciplinary research,training, and translation of science into improved practices and policies” (Stokols et al, 2012). This
study’s intention is shared by those studies on team science, but it differs from those studies in that thisstudy focuses on the R&D of medical devices, which needs inter- or trans-disciplinary collaboration.
In sum, previous research found out the important role of medical doctors in the development of
medical devices as users of medical devices. But the focus of the studies is on the role of medical
doctors as users and as a result not much attention was paid to CME. In addition, a quantitative analysis
on a network for developing a medical device has not been conducted. In order to bridge those gaps, I
intend to look at the effects and difficulties of CME, and to do so especially by bibliometric analysis.

2. Methodology
The research methods for this study include interviews with researchers involved in the development ofartificial retina, and bibliometric analysis of development of cochlear implant.

2.1. Interviews
The purposes of the interviews are to 1) know the degree with which the importance of CME for thedevelopment of medical devices is perceived among interviewees and 2) to know the CME’s
difficulties and how to overcome them qualitatively before conducting quantitative bibliometricanalysis. Co-authorship and research collaboration is not always the same (Katz and Martin, 1997), and7

it is important to know what kind of collaboration takes place at the same time as conducting
bibliometric analysis. The interviewees are medical doctors and engineers who were or are involved in
the development of artificial retina.
Artificial retina (or artificial prosthesis) is a surgical medical device that tries to restore vision bystimulating retina electrically in patients suffering from blindness due to retinitis pigmentosa (RP) or
age-related macular degeneration (AMD) (Ameri et al, 2007). Different from cochlear implant, thismedical device had not been commercialized and was at the stage of clinical trial at the time of theinterviews. I chose this medical device because 1) there are currently competing research teams in theworld, 2) this medical device is an advanced medical device that needs intensive R&D, and 3) there aretechnically common elements between R&D of cochlear implant and artificial retina. I conductedinterviews in the U.S., Germany and Japan in order to increase the generalizability of the findings.
However, since there are many kinds of medical devices, we need caution when generalizing the resultof the interviews. 2

2

There are many kinds of medical devices: medical devices for diagnostic, surgical or rehabilitation

purposes. They can also be classified by application areas such as digestive system, ear/nose/throat
system, urinary system, orthopedic system and so on, or by types of markets (commodity products or
innovative medical devices products) (Mehta, 2008, p.8).

8Interviews were conducted with ten researchers in Japan, at the engineering and medical departmentsof universities and firms. Six interviews were conducted in the U.S. and five interviews in Germany. 3
The information collected in the interviews were facts and beliefs/attitudes related to CME. The
questions I asked in interviews include: what is the current status of the R&D and CME; how CME isimportant for the R&D for medical devices; what the hurdles for collaboration are; and what you needto maintain CME by overcoming the hurdles. The answers to those questions were given in an openended manner. The interviews were recorded, and its contents were transcribed.

2.2. Bibliometric analysis
We analyze CME when developing cochlear implants by bibliometric analysis. The purpose is to lookat the characteristics of CME and its effects on R&D productivity. Cochlear implant is a widely-usedsurgical medical device for assisting a person who has difficulty in hearing by stimulating electricallythe cochlear in internal ear. 4 The reason why I chose this medical device is that 1) cochlear implant is a3Interviews were conducted in Japan in September and October 2008 (3 medical professor, 6

engineering professors, 1 firm manager), in the U.S. in December 2008 (2 medical professors, 2
engineering professors, 1 firm manager), and in Germany in January 2009 (2 engineering professors, 1
firm manager, 2 policy researchers in public research institute).
4

In the U.S., 1.2 million children and adults were estimated as potential implant candidates. The total

number of recipients in the U.S. in 2009 was estimated at 70,000 adults and children, yielding autilization rate of 5.6% among the candidate population. (Sorkin, 2013)9

successful medical device, and there have been R&D efforts of the research teams in the world, 2) theirefforts are well-documented by previous studies, and 3) cochlear implant has common technicalelements with artificial retina. As stated above, we need caution when interpreting the results.
Coauthorship and coinventorship analysis are conducted in order to analyze the network ofcollaboration. The tools used for the analysis are VantagePoint for data mining, and Pajek for analyzing
and visualizing social network (Morel et al, 2009). Bibliographic information is downloaded using
Web of Science and Derwent Innovation Index. We identify if the author or inventor is a medical
doctor, engineer, or other. I define medical doctor as a graduate of medical school irrespective ofwhether he/she currently practices medicine or not. Information on authors or inventors is obtained
from websites of the institutions or websites of themselves. The mapping of the network of CME is
depicted and observed (de Nooy et al., 2005).
As to Web of Science, we used citation index expanded edition and the period is up to September 25,
2010, and as to Derwent Innovation Index, the search period was from 1963 to September 25, 2010.
Search word was “cochlear implant.” The number of hits is 2,910 for articles and 714 for patents. Afterchecking the content, we restricted the data to top 100 authors or inventors in terms of the number of
papers or patents. We chose data on 1,428 articles and 392 patents.
The purpose of conducting bibliometric analysis here is not just to visualize coauthorship or
coinventorship relationships. In other words, visualization is not the purpose but the means to look at
the degree of collaboration between medical doctors and engineers for the development of this medical
device. As Börner and Boyack (2012) pointed out, the purpose of mapping is “simply to visually
10display the results of analysis to enhance communication of those results” and visualization itself is notanalysis.

3. Results
3.1. Interviews
a. United States
There are two major research teams on artificial retina in the U.S. One team, Boston Retinal Implant
Project, is the team composed of researchers at Harvard University and Massachusetts Institute ofTechnology (MIT). The other is the team composed of researchers at University of Southern California(medical school); University of California, Santa Cruz; and Second Sight.5 The former research teamstarted in the late 1980s.6 The latter team started at almost the same period as the Boston project.
Second Sight is a private firm established in 1998 by Alfred Mann, who established Advanced Bionics
in 1993.
In the interviews, the starts of the research projects were explained by an engineering professor (Eng.
Professor A): “the project started from the idea of a medical doctor. He visited our department at theuniversity. At the time, I did not know anything about retinal implant, and he did not know electronics.
He was trying to find an engineer with whom he can work together.” The medical doctor who visited5

The explanation in this section is based on the information at the time of conducting interviews, andmay change afterwards.
6

Boston Retinal Implant Project http://www.bostonretinalimplant.org/ (accessed at November 16, 2014)11

the engineer explained (Med. Professor A) that “the project started in the late 1980s. My specialty was
retinal transplantation and tried to recover the vision of patients who have diseases in retina by
implanting retinal cells. One day I came up with an idea to use microelectronics technology. With thisidea in mind, I contacted many engineers and discussed about its feasibility.” They found out that theyshared a common interest in human vision. Eng. Professor A explained that “we had common interest,
and that was very important when starting the project.” Another engineering professor in anotherresearch group (Eng. Professor B) explained that “a medical doctor working at a university hospital
contacted me. He came to my office and asked me if it was possible to make light into electric signals.
There was a hypothesis that stimulation of retina by implanted electrodes could recover lost vision.” In
those stories, the initiative of medical doctors to contact with engineers and start the projects on theirinitiatives was noteworthy.
Then the importance of CME and its difficulty were pointed out. In the words of Eng. Professor B,“interdisciplinary collaboration is important for developing a medical device. Medical doctors play therole of pull, and engineers play the role of push.” Eng. Professor A said, “engineers have knowledge on
devices that medical doctors would like to use. Medical doctors know that they cannot develop without
collaborating with engineers. Collaboration may be difficult, but necessary.”
As to the difficulties on CME, first, understanding of technical terms was pointed out. Eng. Professor A
told me on his research career: “I have an engineering background, so I needed to study medical
science. In interdisciplinary research, it is necessary to study in order to understand what collaborators12

are saying.” Eng. Professor B explained the same story: “I did not know about medicine and biology.
There is a barrier to speak over disciplines, but you can overcome it if you continue working.”
Second point is about allocation of time and efforts. This may be general problems of collaborative
research. “Problems can happen, for example, if the participants allocate only a little time for the
project. We try to meet at least once a week and understand each other” (Eng. Professor B). Eng.
Professor A explained that “I teach and clinicians work in a hospital. Engineers and medical doctors
have many goals other than the project.”
In order to overcome those difficulties, first, importance of leadership and personality of members werepointed out. Eng. Professor A explained that “the reason why the project goes well is that the leader ofthe project, who is a clinician, is not a person difficult to work with. Another important factor is
personality type of members. Our team is consisted of researchers who are easy to talk to andstraightforward.” Eng. Professor B pointed out that “the role of leadership is important for good teamwork. Team members need to trust each other.” Secondly, the importance of close distance was pointed
out. Med. Professor A explained that “there is a community of scientists in this region. In particular,
researchers at Harvard and MIT are cooperative each other.” Another medical doctor (Med. ProfessorB) pointed out the regional advantage of being in his region. Importance of close distance was pointed
out also by engineers and a firm manager. According to a firm manager (Manager A), “many medical
doctors and engineers participate in the project. Our lesson is that proximity is very important. Being
proximate leads to better results.” Thirdly, the importance of education was pointed out. Med.

13

Professor A observed that “in general, the collaboration between medical doctors and engineers go wellin the U.S. There are well-established systems and programs at major universities.”b. Germany
In Germany, Federal Ministry of Education and Science started a research project called NeuroTechnology in 1994. It provided funding in 1995 for two research projects for developing artificial
prosthesis: epiretinal-type system and subretinal-type system. The government funding for thoseprojects continued until 2003. There are private companies that are trying to commercialize each typeof artificial retinas: Intelligent Medical Implants for epiretinal method and Retina Implant for subretinal
method.
One of the research team, according to one engineering professor (Eng. Professor C), was composed ofinterdisciplinary members. He explained that “when we started a project, the backgrounds of 12 teammembers include mathematics, computer science, physics, engineering, material science, optoelectronics, opt-biology, neurobiology, and ophthalmology.” He commented on the importance ofcollaboration that “medical doctors, engineers, and biologists sit on the same table and started
discussing on the project. At first, they said that it is impossible to develop such an advanced medical
device. Then interesting thing happened. After three months, we started to trust each other and to thinkthat we may be able to solve the problem by working together.”In the interviews, a couple of difficulties for CME were pointed out. Firstly, the difficulty ofmaintaining collaborative relationship among members was pointed out. One analyst of medical
devices development at a public research institute (Analyst A) explained that it is difficult for medical
14

doctors and engineers to maintain an equal partnership, since clinicians tend to think that only theyknow what is good for patients. Secondly, as to a problem of time pressure, especially for clinicians,
another researcher at a public research institute (Analyst B) observed that clinicians are busy and thatmakes it difficult for medical doctors and engineers to collaborate on a research project, since it isdifficult for clinicians to have a balance between patients and research.
In order to overcome those difficulties, the importance of good leadership and communication wasemphasized. As to the importance of good leadership, Eng. Professor C said, “clinicians in general play
the role of a leader and tend to dominate a multidisciplinary research team. It is necessary for such
person to understand he should contribute as a team member according to his expertise.” He added that“our members have a cooperative personality. Members say what they would like to say, and we think
there are no stupid questions.”c. Japan
In Japan, NEDO funded a project on artificial prosthesis for 5 years between 2001 and 2006. NEDO isa public funding agency in applied R&D area. The leader of the project was at the medical school of
Osaka University. The development of the system was conducted by a private firm, Nidek. Nidek was
in charge of the development of technologies and the device system. Nara Institute of Science andTechnology and the engineering department of Osaka University collaborated with regards to thedevelopment of the electronic device.
The difference with the U.S. and German groups was that a company was given a major role from thestart of the project and “user-led” force by medical doctors was stronger, both of which reflected the15

fact that Japanese team was a late comer and needed to catch up quickly. In the interview, one medical
doctor (Med. Professor C) explained on the role of medical doctors that “we are in a position ofevaluating the product the firm produced. I have a periodic meeting with the firm. We examine theproduct by embedding it in a rabbit’s eye.” A company participant (Manager B) said, “medical
professors made many requests based on the result of the experiments, for example, on the shape of thedevice.” Another medical professor (Med. Professor D) commented that “it is difficult for researchers
at engineering department to do research on medical devices by themselves. Such research should be
led by medical doctors. It is necessary to examine the reaction of human body to the device.”
Although the importance of CME was pointed out in the interviews, its difficulties were emphasized.
Firstly, as to understanding of technical terms, one engineering professor (Eng. Professor D) explainedthat “when we started research, we did not understand the language of other disciplines. It takes time tounderstand the field.” Another engineering professor (Eng. Professor E) explained that he did notunderstand at the start of the joint research the words like “optic disk,” “vitreous humour,” “retinitis
pigmentosa” or “macular degeneration.” Secondly, different expectations and goals of medical doctors
and engineers were pointed out. Yet another engineering professor (Eng. Professor F) explained that“medical doctors expect a medical device that can be used immediately for patients, even if the device
lacks novelty. However, if the medical device lacks novelty, engineers cannot write a research article.”
Thirdly, there were many comments on the difficulty in communication, Eng. Professor D pointed outthat “there is a problem of communication between medical and engineering researchers. In general,clinical researchers are all busy and do not have enough time to respond to engineer’s request
16

immediately.” Another engineering professor (Eng. Professor G) explained that “medical professor’s
thinking is that they have absolute authority in their specialty, and as a result it is difficult to doresearch in a bottom-up approach,” which makes frank bottom-up communication difficult.
In order to overcome those difficulties, the importance of frequent communication and education on
medical engineering were pointed out. As to frequent communication, Eng. Professor E observed that“in the project, we had periodic meetings. We took enough time in the meetings for discussion andengineers started to understand what medical doctors are trying to say.” As to the importance of
education on medical engineering, another medical professor (Med. Professor D) emphasized that “lackof human resources in this field is a large problem. In Japan, it is when you start a joint research projectthat you start learning other fields and look for common language.”In sum, medical doctors and engineers perceive that CME is one of the important factors to the successin developing medical devices. From those observations, we could reasonably assume that there is
CME if there is coauthorship or coinventorship relationship between them. At the same time, the goodcollaborative relationship is pointed out to be difficult to be built and be maintained. There are hurdles
to overcome.
Various hurdles for building a collaborative relationship and a couple of factors that promotecollaboration were pointed out, although those are not meant to be exhaustive. Firstly, mostinterviewees pointed out the importance of good leadership, personality of members and goodcommunication for successful collaboration. Such good collaboration would make it enjoyable for17researchers to learn the unfamiliar field and learn from each other. Relating to that, close distance of
researchers was pointed out to be effective for maintaining more frequent interactions. Secondly,
programs on medical engineering at universities not only provide education to students who want to doresearch in the field of medical technology, but also function as a place to conduct R&D on medical
devices cooperatively.

3.2. Bibliometric analysis
Before explaining the result of the bibliometric analysis, I explain the R&D process of cochlear implantbriefly.7 In 1957, Professor Eyries, who was of the medical faculty in Paris, tried to give a deaf patient
some hearing by an electrode implanted into his ear. Eyries collaborated with his colleague Djourno,
who was studying electrical stimulation of the auditory nerve in animals. Dr. House, an ear surgeon in
Los Angeles, tried to implant a more complex electrode into a deaf man in 1961, and collaborated withan engineer to construct it. Professor Simmons, who was at Stanford University Medical School, triedin 1962 what House did. He implanted a six-electrode device in 1964, collaborating with an expert in
auditory psychophysics.
By the mid-1970s, other research groups were involved. At the University of California at San
Francisco (UCSF), Dr. Michelson, who was a physicist-turned-otologist, implanted electrodes for four
patients. In Australia, in 1970, Professor Clark, a chair in otolaryngology at the University of
7This section draws on Blume (2009), Chapter 2 “The Making of the Cochlear Implant.”

18

Melbourne, started developing multiple electrodes inserted at different positions in the inner ear and a
prototype was implanted into the first volunteer in 1978.
Cochlear implantation gained credibility in the profession, and industry became interested in the late1970s. 3M was the first company to market a cochlear implant in the U.S. 3M made contractual
agreements with House and the Hochmairs, Austrian electrical engineers, in 1981, and the House/3M
device became the first cochlear implant to be approved by FDA in 1984. Clark’s industrial partner was
Nucleus. The Nucleus implant became the second system to be granted FDA approval in 1985. The
ownership of the 3M/House device was sold to the Nucleus-daughter Cochlear Ltd. (Cochlear
Corporation) later. Three manufacturers now dominate the world market. The Cochlear Ltd. is themarket leader. The other manufacturers are MedEl (an Austrian firm established by the Hochmairs in1989) and Advanced Bionics, which developed a commercial implant based on work at UCSF.

a. Analysis on coauthorship and coinventorship
Figure 1 shows coauthorship relations.8 Each node shows a researcher and each line shows acoauthorship relation. The number in the node (1-10) refers to the ranking of researchers in terms of

8

Since appropriate number of nodes for looking at network relationship is 500 at the most, only

researchers with more than or equal to three articles were included and the number of researchers in the
figure was reduced from 2,267 to 506. By including only coauthorship relation with more than or equal
to 4 coauthored articles, the number was further reduced to 314. Although the number is reduced, thenumber of researchers is larger since there are coauthors to those researchers.
19the number of published papers. The wider the width of a line is, the larger the number of coauthoredarticles. The color of nodes shows type of occupations: yellow for a medical doctor, green for anengineer, red for others (including biomedical scientists), and blue for unknown. There are medical
doctors, engineers, and biomedical scientists, and collaborative relationship of those researchers can beobserved.
Figure 2 shows coinventor relationship.9 The largest group is at Cochlear Ltd. and other group’s sizes
are almost the same. What is different from the coauthorship relations is that there are not many
medical doctors in the research groups, and most of the researchers belong to private companies. Only
the research group at Cochlear Ltd. includes medical doctors.
(Insert Figure 1 and Figure 2)
Figure 3 revised the size of the nodes in Figure 1 based on the size of “betweeness centrality” of eachnode, that is, the proportion of all geodesics between pairs of other nodes that include this node (deNooy, et al, 2005).10 Geodesics means the shortest path between two nodes. The size of this indicatormeans the degree with which a node occupies the central position in the network. This graph shows9

The inventors with more than or equal to 2 applications and with more than or equal to 2 coinventor

relationships are included. The number was reduced from 506 to 177.
10

There are other indices for comparing the centrality of nodes, such as “degree centrality” and“closeness centrality.” Degree and closeness centrality are based on the reachability of a person withina network, and the concept of betweeness depends on the idea that the more a person is a go-between,
the more central his or her position in the network. Both indices can be used for the current purpose.
20

how medical doctors occupy the central position in each research group. Likewise, Figure 4 is madebased on Figure 2. In the patent data, engineers occupy central positions in each research group. It isinteresting to note that there are no centrally-positioned dominant researchers different from the data on
research articles.
(Insert Figure 3 and Figure 4)
Next, “network betweeness centralization” of each research group was calculated. “Network
betweeness centralization” means the variation in the betweeness centrality of nodes divided by the
maximum variation in betweeness scores possible in a network of the same size. The higher theindicator is, the more centralized the network is. Network betweeness centralization based on research
articles is larger than that based on patents, which means that there are more dominant research leadersin research groups at article-writing phase11 as Figure 3 and 4 show.
Cohesion of each research groups is examined next. For this purpose, average degree of nodes was
examined. Degree is defined as the number of lines incident with it, and average degree of nodes is
11

As to the data on research articles, network betweeness centralization of research groups at Medical

University Hannover, Johns Hopkins University, University of Sydney, University of Southern
California, and Medical University of Vienna was 0.817, 0.526, 0.809, 0.643, and 0.463 respectively.
As to the patent data, network betweeness centralization of research group at Cochlear Ltd., Advanced
Bionics, Medtronic, MED-EL, and Greatbatch, Ltd. was 0.522, 0.373, 0.461, 0.598, and 0.314
respectively.

21

calculated by averaging the degrees of all the nodes in a research group.12 The difference between thesizes of “average degree” of the research groups in data on articles and patents was not statisticallysignificant.13

b. Relationship between CME and research group’s productivity
The relationship between the total number of articles14 and the proportion of the number of thecoauthorship relations between a medical doctor and an engineer to the total number of thecoauthorship relations (%) for each research group is examined. A research group is defined as a groupof researchers who shows coauthorship relationship in Figure 1, and one or more of whose members
12“Density” is another indicator for measuring cohesion. Average degree of all nodes is a better index,

because density depends on network size and is not appropriate to use for comparing networks ofdifference sizes.
13

As to research articles data, average degree for the research groups at University of Sydney, Medical

University Hannover, Johns Hopkins University, University of Southern California, and Medical
University of Vienna are 7.10, 6.20, 7.44, 4.0, and 7.45 respectively. As to the data on patents, average
degrees for the research groups at Cochlear Ltd, Advanced Bionics, Medtronic, MED-EL andGreatbatch, Ltd. are 7.30, 6.75, 12.6, 6.32, and 13.5 respectively
14

The number is calculated as the sum of the number of articles written by an author or authors which

at least include a “medical doctor”, an “engineer”, or “other” in Figure 1 or Figure 2. Duplication isdeleted in this analysis. In other words, when A, B, and C in the same research group write a paper
jointly, the number of papers of the group is calculated as 1, not 3.

22are among the top 20 authors in terms of the number of articles written. The correlation coefficients forcoauthorship and coinventorship are positive and statistically significant at 10% and 1% respectively.15
In addition, the correlation between centralization and the number of articles or patents for researchgroups, and the correlation between cohesion (average degree of nodes) and the number of articles orpatents were examined. Any statistically significant relationships were not found. In other words, agroup where one dominant research leader occupies the central position or a group with higher
cohesion of members does not produce more research articles or patents. The reason would be thatcollaborative relationship among research members are not based on one-way command and control
from a leader but on more equal and looser interdisciplinary collaborative research relationship among
members. As to cohesion, the reason would be that each member collaborates not with all, but with apart of members.

c. Dynamics of CME
Figure 5 shows the change in proportion of types of coauthorship, that is, whether between a medical
doctor and an engineer (we call it type 1 collaboration), between medical doctors (type 2 collaboration),or between engineers (type 3 collaboration), in articles. Proportion of the type 2 collaboration is highsince the late 1980s up to the present. This is expected from Figure 1, since there are many medical
15

Correlation coefficient between the number of articles and the proportion is 0.620 (p-value=0.056,n=10) and correlation efficient between the number of articles and the proportion is 0.996 (pvalue=0.0043, n=4).
23

doctors who write an article, collaborating with each other. Proportion of the type 1 collaboration ishigh in the early 1980s. Although it declined, the proportion of the type 1 collaboration is maintained at20-30% and such type of collaboration is sustained in the R&D process.
Likewise, Figure 6 shows the change in proportion of each type of coinventorship, in patents. Different
from the coauthorship, the type 3 collaboration, conducted at private firms, dominates.
(Insert Figure 5 and Figure 6)

In sum, the following is observed in the bibliometric analysis.
1) In data on coauthorship, medical doctors themselves are authors to research articles and theimportant role played by medical doctors and CME, as was observed in the interviews, is observed(Figure 1). Figure based on network betweeness centralization shows the important role played by
medical doctors in networks of researchers (Figure 3) (3.2 a.).
2) There are few medical doctors in the map of coinventor relationship compared with coauthorship
relationship (Figure 2). The reason would be that the role of medical doctors and CME is important,particularly during the stage of concept generation and reflection of needs, and the role of engineers infirms becomes indispensible in commercialization stage. In addition, the network is more centralized inresearch group on articles than that on patents, suggesting that creative activities in a group at research
stage is led more by a few dominant researchers than at applied stage (3.2 a.).
3) We found the positive correlation between the number of articles for each of the research groups,
and the proportion of the number of the coauthorship between a medical doctor and an engineer of the24group to the total number of the coauthorship relations. Likewise, we found the positive correlation
between the number of patents and the proportion of coinventorship relations (3.2 b.).
4) Either for data on coauthorship or on coinventorship, CME is important during the initial stage of
R&D. The more R&D proceeds toward commercialization and later stage, the larger the role ofengineers becomes (3.2 c.).

4. Discussion
By conducting interviews, we found that medical doctors and engineers perceive that CME is one of
the key factors to the success in developing medical devices. By conducting bibliometric analysis, wefound the importance of the role played by medical doctors and CME. However, in the interviews, it
was pointed out that the good collaborative relationship is difficult to maintain (3.1.). In this section,
we would like to discuss why it is difficult.
First explanation is general difficulty in conducting interdisciplinary research.16 The difficulty, in
general, includes differences in methods of inquiry, scientific standards of evidence, communication
structures, socialization processes, external recognition, and so forth (Corley et al., 2006). Clinicalstudy is a system of knowledge that intends to cure patients, while engineering is a system of
16

In general, the approach of cross-disciplinary research are called as either multidisciplinary, interdisciplinary,or transdisciplinary in the increasing level of disciplinary integration (Stokols, D. et al. 2012). In this study, theterm interdisciplinary research refers to R&D on medical devices by drawing on and integrating knowledge of
medical sciences and engineering, and relates to both interdisciplinary and transdisciplinary research approaches.

25

knowledge for designing a thing that is useful for people. Although there are overlaps of thosedisciplines, there still remain the difficulties.
Second explanation is high degree of tacitness of medical knowledge. Knowledge is a concept different
from information (Davenport and Prusak, 1998):”knowledge is a fluid mix of framed experience,values, contextual information, and expert insight that provides a framework for evaluating andincorporating new experiences and information.” Michael Polanyi (1958), who proposed the concept oftacit knowledge, was originally trained as a medical doctor. He frequently refers to the education of
medical doctors when explaining the concept in his book Personal Knowledge17. The personal
knowledgeness of medical knowledge would be the reason why medical doctors take an initiative in thedevelopment (or reason of “user-led” type innovation).
Third explanation relates to special status of medical profession. As Freidson (1970) explains, medical
doctors possess “something of a monopoly over the exercise of its work” and “special privilege of
freedom from the control of outsiders” because of their high skill and knowledge, and society’s trust inthem. As a result, other occupations tend to be subordinate to medical doctors in authority andresponsibility. Freidson, a sociologist, also points out the characteristic of the mind of clinicians, or
17

Polanyi explains as follows: “Connoisseurship, like skill, can be communicated only by example, notby precept. …[T]o be trained as a medical diagnostician, you must go through a long course ofexperience under the guidance of a master. Unless a doctor can recognize certain symptoms, e.g. theaccentuation of the second sound of the pulmonary artery, there is no use in his reading the descriptionof syndromes of which this symptom forms part.” (Polanyi, 1958, pp.54-55)

26

“clinical mind,” as compared to theoretician or investigator. A practitioner of medicine “comes
essentially to rely on the authority of his own senses, independently of the general authority of traditionor science.” (Freidson, p.168-170). These characteristics of medical doctors would lead to the difficultyin CME, in the situation where engineers do not have to be subordinate and need to have autonomy in
the creative R&D activity.
If CME is essentially difficult as is explained above, the initiative of a medical doctor as a user alone,although it is important, does not make it possible to overcome those hurdles for CME. There would
need to be other factors. First, absorptive capacity of both medical doctors and engineers would be
important. Cohen and Levinthal (1990) argued that the ability to identify, interpret, and exploit new
knowledge is critical to innovative capabilities, and label it absorptive capacity. Their argument focuses
on firms, but absorptive capacity of individuals is necessary as a precondition for absorption oftechnologies to occur (Lane, Koka, and Pathak, 2006). In addition to that, absorptive capacity isimportant not only for absorption of technologies by a firm, but for conducting collaborative R&D in
an interdisciplinary field.
Second, proximity between medical doctors and engineers is important. Boschma (2005) pointed out
there are five forms of proximity (geographical, cognitive, organizational, social and institutional)
when conducting a collaborative project. He defines cognitive proximity as a function of the similarity
between actor’s knowledge bases. Boschma argued that these forms of proximity may substitute eachother. When there is no cognitive proximity, other elements of proximity helps. Therefore regional
advantage, long historical relationship or past experiences of collaboration compensate for lack of27

cognitive proximity, as was pointed out in the interviews. Or cognitive proximity itself can be nurtured
by education. In case of development of medical devices, since most of the knowledge bases of medical
doctors and engineers are not shared, efforts to shorten the distance in the other dimensions ofproximity would be important for increasing the productivity of the collaboration.

5. Conclusion
In this paper, by interviewing medical doctors and engineers involved in R&D of artificial retina, wefound that medical doctors and engineers perceive that CME is one of the keys to the success indeveloping a medical device, but that the good CME is difficult to maintain. By looking at suchcollaboration in bibliometric analysis of research articles and patents, we found the important role ofmedical doctors and CME. Central positions are occupied by medical doctors in the researcher’s
network. For each of the research groups, there is positive correlation between the number of articles orpatents and the degree of CME represented by coauthorship or coinventorship. In other words, more
CME is seen in the more productive R&D group. In addition, data shows that the CME is importantduring the initial stage of R&D.
Considering those findings, research teams that are able to overcome the difficulties in CME, as arepointed out in the interviews, achieve close collaboration and lead in the development as can beobserved in bibliometric analysis. In other words, development of a medical device needs not only the“user-led” forces derived from medical doctors but also close interdisciplinary collaboration between a
medical doctor as a user of the device and an engineer as a designer of the device.

28

For such collaborative efforts to succeed, absorptive capacity of both sides and proximity between
them are important, since there are barriers between a medical doctor and an engineer including
cognitive (disciplinary), organizational, social, and institutional barriers. To overcome those barriers,
education, geographic proximity, and good leadership or member’s personality is effective. Those
could promote some elements of proximity to compensate for lack or shortage of other elements ofproximity such as cognitive proximity among others.
In order to get stronger results on (1) causation between CME and performance of R&D on medical
devices, and (2) temporal pattern of CME, it is necessary to do studies on more cases of R&D of
medical devices using the same methodology, and do interviews or a survey in other medical specialty.
Also it would be interesting to do a longitudinal bibliometric analysis on R&D of medical devices of a
firm or industry, and see how the pattern of collaboration is changing with the advent of open
innovation.
The important implication of this study for R&D management is that bibliometric analysis on articles
and patents, when incorporating data on whether a researcher is either a medical doctor or an engineer,is effective to monitor or evaluate a R&D program or project on medical technology by ainterdisciplinary research team, either conducted by a government research institute, a university, or a
firm. Especially it would provide valuable data when evaluating the degree of interdisciplinary
collaboration of a large government R&D program on a medical device.

29

Acknowledgement
The author appreciates the helpful comments of two reviewers, and financial support from 1) the
Economic Research Institute of the Japan Society for the Promotion of Machine Industry, with thefunding of JKA through its Promotion funds from KEIRIN RACE, for conducting interviews, 2) the
Watanabe Memorial Foundation for the Advancement of Technology, for conducting bibliometricanalysis, and 3) the Institute for Future Engineering for presenting a part of this study at the 3rd Atlanta
Conference on Science and Innovation Policy. The author would like to thank all the researchers,
engineers and medical doctors for sharing their time during interviews.

Reference
Ameri, H., Wieland, J.D., Humayun M.S. (2007). Biological Considerations for an Intraocular Retinal
Prosthesis, in: Humayun, M.S., Weiland, J.D., Chader, G., Greenbaum E.(Eds), Artificial Sight: Basic
Research, Biomedical Engineering, and Clinical Advances. Springer, New York, pp.1-29.
Blume, S.S. (1995) Cochlear implantation: establishing clinical feasibility, 1957-1982, in Gelijns C.,
and N. Rosenberg, eds. 1995b, pp.97-124.
Blume, S.S. (2009) The Artificial ear: cochlear implants and the culture of deafness. Rutgers
University Press, Piscataway.
Börner, K. and Boyack, K.W. “Mapping interdisciplinary research” pp.457-460. in The Oxford
Handbook of Interdisciplinarity. Edited by Frodeman, R., Klein, J.T., and Mitcham, C. Oxford
University Press.

30

Boschma, R.A. (2005) Proximity and innovation: a critical assessment. Regional Studies. 39, 61-74.
Chatterji, A.K., Fabrizio, K.R., Mitchell, W. and Schulman, K.A. (2008) Physician-industry
cooperation in the medical device industry. Health Affairs 27(6), 1532-1543.
Corley, E.A., Boardman, P.C. and Bozeman, B. (2006) Design and the management of multiinstitutional research collaborations: theoretical implications from two case studies. Research Policy 35,
975-993.
Cohen, W. M. and Levinthal, D.L. (1990) Absorptive capacity: a new perspective on learning andinnovation. Administrative Science Quarterly. Vol.35, No.1, 128-152.
Davenport, T., and Prusak, L. (1998) Working knowledge: how organizations manage what they know.
Harvard Business School, Cambridge, MA.
de Jong, J.P.J., and Freel, M. (2010) Absorptive capacity and the reach of collaboration in hightechnology small firms. Research Policy 39 (2010). 47-54.
de Nooy, W., Mrvar, A. and Batagelj, V. (2005) Exploratory social network analysis with Pajek.
Kindle Edition. Cambridge University Press, Cambridge.
De Vet, J.M. and Scott, A.J. (1992) The Southern California medical device industry: innovation, newfirm formation, and location. Research Policy 21, 145-161.
Finkelstein, S.N., Neels, K. and Bell, G.K. (1995) Innovation in cardiac imaging, in Gelijns C., and N.
Rosenberg, eds. 1995b, pp.125-154.
Freidson, E. (1970) Profession of medicine: A study of the sociology of applied knowledge. Universityof Chicago Press, Chicago.
31Fuchs, V.R. (1998) Who shall live?: health, economics, and social choice. Expanded Edition. World
Scientific Publishing, River Edge, NJ.
Gelijns, C., and Rosenberg, N. (1995a) From the scalpel to the scope: endoscopic innovations ingastroenterology, gynecology, and surgery, in Gelijns C., and N. Rosenberg, eds. 1995b, pp.67-96.
Gelijns C., and Rosenberg, N. eds. (1995b) Sources of medical technology: universities and industry.
National Academy Press, Washington, D.C.
Ijichi, T., Yoda, T. and Hirasawa, R. (1993) Mapping R & D Network Dynamics: Analysis of theDevelopment of Co-author and Co-inventor Relations. Journal of Science Policy and Research
Management, Vol. 8, No.3, 263-275.
Katz, J.S. and Martin, B.R. (1997) What is research collaboration? Research Policy, 26. 1-18.
Lane, P.J., Koka, B.R. and Pathak, S. (2006) The Reification of Absorptive Capacity: A Critical
Review and Rejuvenation of the Construct. Academy of Management Review. Vol.31, No.4, 833-863.
Lettl, C., Herstatt, C.H. and Gemuenden, H.G. (2006) Users’ contributions to radical innovation:evidence from four cases in the field of medical equipment technology. R & D Management 36, 251272.
Luthje, C. (2003) Customers as co-inventors: an empirical analysis of the antecedents of customerdriven innovations in the field of medical equipment. Proceedings of the 32nd European Marketing
Academy Conference, Glasgow, UK.
Mehta, Shreefal S. Commercializing Successful Biomedical Technologies: Basic Principles for theDevelopment of Drugs, Diagnostics and Devices. Cambridge University Press. 2008.
32

Metcalfe, J.S., James, A. and Mina, A. (2005) Emergent innovation systems and the delivery of clinicalservices: the case of intra-ocular lenses. Research Policy 34, 1283-1304.
Morel, C.M., Serruya, S.J., Penna, G.O., and Guimaraes, R. (2009) Co-authorship network analysis: apowerful tool for strategic planning of research, development and capacity building programs onneglected diseases. PLoS Neglected Tropical Diseases 3(8), online.
Morlacchi, P., and Nelson, R. (2011) How medical practice evolves: learning to treat failing hearts with
an implantable device. Research Policy 40, 511-525.
Polanyi, M. (1958) Personal knowledge: towards a post-critical philosophy. University of Chicago
Press, Chicago.
Powell, W.W., and Grodal, S. (2006). Chapter 3: Networks of Innovators. Pp.56-85. In The Oxford
Handbook of Innovation. Edited by Fagerberg, J., Mowery, D.C., and Nelson, R.R. Oxford University
Press.
Saltzman, W.M. (2009) Biomedical engineering: bridging medicine and technology (kindle edition).
Cambridge University Press, New York.
Schuman, J.S., Puliafito, C.A. and Fujimoto, J.G. eds. (2006) Everyday OCT: Handbook for clinicians
and technicians. Slack Incorporated, Thorofare, NJ.
Shah, S.G.S., and Robinson, I. (2006) User involvement in healthcare technology development andassessment: structured literature review. International Journal of Health Care Quality Assurance 19(6),500-515.

33

Shaw, B. (1985) The role of the interaction between the user and the manufacturer in medical
equipment innovation. R & D Management 15(4), 283-292.
Sorkin, D.L. (2013) Cochlear implantation in the world's largest medical device market: utilization andawareness of cochlear implants in the United States. Cochlear Implants Int. 14(Suppl 1): S4–S12.
Spetz, J. (1995) Physicians and physicists: the interdisciplinary introduction of the laser to medicine, in
Gelijns C., and N. Rosenberg, eds. 1995b, pp.41-66.
Stokols, D. et al. (2012) Chapter 32: Cross-disciplinary team science initiatives: research, training, andtranslation. In The Oxford Handbook of Interdisciplinarity. Edited by Frodeman, R., Klein, J.T., andMitcham, C. Oxford University Press. pp.471-493.
US FDA. Is The Product A Medical Device?
http://www.fda.gov/medicaldevices/deviceregulationandguidance/overview/classifyyourdevice/ucm051
512.htm (accessed at November 16, 2014)von Hippel, E. (1988) Sources of innovation. Oxford University Press, New York.
Yin, R.K., 1994. Case Study Research: Design and Methods (Second Edition). Sage Publications,Thousand Oaks, California.

34

Univ. Hannover, Univ.
Freiburg

Univ. of Iowa, Johns
Hopkins University

8

5

10

9

2

Univ. of Leuven

Medical Univ ofUniv. of Sydney, etc. Vienna, etc.

1

7
6

3

Univ. of Southern
California

Arizona State Univ. etc.

Athens Univ.

4

Medical doctor Engineer

Other Unknown

Figure 1: Coauthorship relationship among researchers related to cochlear implant

35

Advanced Bionics Corp.

MED-EL
10
6

Cochlear Ltd.
8

3

4

1
5

9

2

Cochlear Ltd., Medtronic Inc.

7

Medical doctor

Engineer

Other Unknown

Figure 2: Coinventorship relationship among researchers related to cochlear implant36

Univ. Hannover, Univ.
Freiburg

Univ. of Iowa, Johns
Medical Univ of
Hopkins University Univ. of Sydney, etc. Vienna, etc.

592Univ. of Leuven

8

10
1

7
6

3

Univ. of Southern
California

Arizona State Univ. etc.

Athens Univ.

4

Medical doctor Engineer

Other Unknown

Figure 3: Centralization of nodes (coauthorship relationship among researchers related tocochlear implant)37

Advanced Bionics Corp.
MED-EL

10

6

Cochlear Ltd.

8

3

4

1

Greatbatch Ltd.

52

Cochlear Ltd., Medtronic Inc.

9
7

Medical doctor Engineer

Other Unknown

Figure 4: Centralization of nodes (Coinventorship relationship among researchers related
to cochlear implant)38

proportion of type of coauthorship

100%
90%
80%
70%
60%
MD x ENG

50%

MD x MD40%

ENG x ENG

30%

20%
10%

1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009

0%

Note: MD: medical doctors, ENG: engineers

Figure 5: Change in proportion of types of coauthorship in articles related to cochlear
implant

39

90%
80%
70%
60%
MD x ENG

50%

MD x MD40%

ENG x ENG

30%

20%
10%

2010

2008

2006

2004

2002

2000

1998

1996

1994

1992

1990

1988

1986

0%
1984

proportion of type of coinventorship

100%

Note: MD: medical doctors, ENG: engineers

Figure 6: Change in proportion of types of coinventorship in patents related to cochlear
implant

40