- © 2008 American Dental Education Association
Abstract
This report describes the research productivity of the members of the International Association for Dental Research (IADR) Behavioral Sciences and Health Services Research Group and examines personal and professional factors related to greater productivity. The findings from previous studies suggested there might be gender discrimination in opportunities for women faculty. Members on the active membership list for this IADR group were surveyed by email. Most were dentists, and three-quarters had external funding for their research. The primary outcome measure was the number of self-reported published articles in PubMed in the preceding twenty-four months. The mean number of these publications was 4.9 (SD=5.1). Gender and time in research were the best predictors of research productivity of this population. There was no difference in time for research between the men and women in this study. Controlling for gender, the best single predictor of research productivity remained percent time spent in research. Overall, the members of the IADR group spent almost three times as much time in research and were more than twice as productive as faculty members as a whole as described in earlier studies. In view of the current emphasis in many countries on addressing the social and behavioral determinants of oral health disparities, the productivity of this area of dental research is very important. Trends toward clinically oriented, non-research-intensive dental schools in the United States and reductions in time and funding available to conduct research should be of concern.
There has been an effort in many nations throughout the world to increase dental research productivity in response to increased emphasis on the social and behavioral determinants of oral health disparities. A recent database study examined this productivity, although it gave little insight into factors impacting individual investigators.1 The United States, United Kingdom, Japan, and Scandinavia were found to be the most productive areas in terms of dental research publications, while the United Kingdom had the highest productivity rates per researcher. Many of the developing countries show rising numbers of publications. Interestingly, the authors of the database study argued that the dental research productivity of the wealthier countries may be stagnating.1 A U.S. survey done in the early 1980s, which unfortunately had a low response rate (31 percent), examined factors associated with productivity and found interest in research, number of journal subscriptions, consulting time per week, and research time per week were the best predictors of the number of publications during a dental research career.2
Another study surveyed a random sample of full-time faculty in U.S. and Canadian dental schools, but was limited to dentists in clinical departments.3 That study, with a response rate of 69 percent, examined gender differences associated with research productivity. The survey found male faculty members published significantly more articles than the female faculty members. While the researchers found no difference in weekly hours devoted to academic pursuits between men and women, the women were less likely to obtain external grant support, less likely to feel their department chair emphasized research, and less likely to have the autonomy and support of colleagues to conduct research.
Similarly, a full-time educator survey was conducted among dental educators in the United States listed on the membership roster of the American Dental Education Association (ADEA) in 2001.4 That survey had a response rate of 40 percent and may have been biased by failure to include research faculty members who did not belong to ADEA. This survey found that male and female faculty members did not differ in average work hours per week, time spent on research, office or lab space, or protected time for research. However, the female faculty members spent more time on teaching and perceived the work environment to be less supportive. The women faculty members were more likely than the men to work in dental hygiene, pediatric dentistry, dental public health, radiology, or the behavioral sciences.
The purpose of this report is to describe the research productivity of the members of the International Association for Dental Research (IADR) Behavioral Sciences and Health Services Research Group and to examine personal and professional factors related to greater productivity. Earlier literature3,4 suggests that differences in research productivity between female and male faculty members merit further exploration. The vitality of this area of research is important because of current emphasis on addressing the social and behavioral elements of oral health disparities throughout the world.
Methods
The participants in this study were current members of the IADR Behavioral Sciences and Health Services Research Group. The list of members was obtained from the records of the IADR as of August 2005. Of the 313 non-student members, 294 had an email address.
Survey
Members on the active membership list were surveyed by email. The email directed the recipient to a website to complete the survey using commercial survey software (QuestionPro Survey Software, Seattle). A modification of the Dillman tailored design method was used to organize the survey.5 A notice of the survey was placed in the research group newsletter, and the survey was discussed at the group business meeting. Members received an initial advance letter, followed by an invitation to participate and three reminders. The survey was conducted between September and December 2005.
The Institutional Review Board of the University of Washington approved the study. The elements of informed consent were contained in an introductory section of the survey itself. Those surveyed were told that the purpose of the survey was to gain a better understanding of the activities and needs of the members of the group and plan for the future. They were told that the survey was voluntary and would take about ten minutes and that their individual answers would be kept confidential and analyzed and published only in the aggregate.
The instrument consisted of sixty-two items divided into five sections: 1) research, 2) employment, 3) teaching, 4) “about you,” and 5) overall professional satisfaction. Except for the professional satisfaction questions, the survey questions were new and written by the authors. The questions and instrument were reviewed by officers of the group, pretested with a small group of members internationally, and then modified for use.
Outcome Measure
The primary outcome measure was the number of self-reported published articles in PubMed in the preceding twenty-four months. No differentiation was made between first author and others. Two additional outcome measures were evaluated: an impact factor weighted score and the average impact factor weighted score. The correlation between the outcome measures was 0.75, and the results obtained in analyses were not different from analyses using the total number of articles. Thus, only results for the total score are presented here.
The research section included the research discipline, published articles, presentations at scientific meetings in the last twenty-four months, books published, service as an editor or associate editor of a journal, service as a grant or journal reviewer, and research funding and the source of that funding. The employment section included whether the respondent was a dentist, number of hours worked per week, self-reported percentage of time spent in research, whether the respondent was tenured, and whether the individual served as a research mentor for another faculty member.
The teaching section included questions about the level of topics students were taught, teaching in continuing education courses, whether the respondent’s program was accepting research trainees, eligibility for traineeships, and whether there was a stipend attached to the traineeship. The “about you” section included year of highest degree, year of birth, gender, what country the respondent worked in, and several questions about participation in meetings and the committee structure of IADR.
The professional satisfaction section consisted of a job satisfaction scale of seven questions taken from the larger fifty-four-item Dentist Satisfaction Survey,6 in which the respondent used a five-point Likert scale from strongly agree to strongly disagree. The questions dealt with fulfillment of earliest and current career aspirations, desire to change career path, willingness of the respondent to choose the same career again, likelihood of a career change in the next five years, and whether the current path was taking the individual where he or she could make the best contribution. After recoding to account for reversal of some questions, the final scale scores were totaled and could range from 7 to 35, with 35 representing a high level of satisfaction. The Cronbach alpha was .82, indicating a satisfactory level of internal consistency for the scale. No further scale validation was done.
The data were downloaded from the proprietary survey website database and entered into an SPSS database (version 15.0) and cleaned. Analyses were conducted using SPSS. Bivariate relationships were evaluated with t-tests, chi-square analyses, and Pearson correlation. General linear regression was used to evaluate a model of both personal and professional factors and their influence on research productivity.
Results
One hundred seventy-seven surveys contained usable data. The response rate adjusted for bad email addresses was 63.0 percent. The percentage of participants who either never started the questionnaire or started but quit was 22.4 and 14.6 percent, respectively. The incomplete response difficulty was caused by problems with the commercial online survey software that occurred after the survey was pretested and fielded. Not all individuals completed all items.
The mean number of self-reported publications in PubMed in the preceding twenty-four months was 4.9 (SD=5.1). The range was 0–29. Figure 1⇓ is a histogram of the number of self-reported publications. Figure 2⇓ provides data on the frequency of publication overall in the twenty journals most frequently published in by the respondents.

Distribution of publications in PubMed journals in the last twenty-four months self-reported by members of the IADR Behavioral Sciences and Health Services Research Group in 2005 (N=177 respondents)

Frequency of publication overall in the twenty journals most frequently published in as reported by members of the IADR Behavioral Sciences and Health Services Research Group in 2005 (not adjusted for possible multiple reporting of the same article by different respondents)
Of 177 respondents, seventy-seven (43.5 percent) were female. The mean year of the last university degree earned was 1989 (SD=11). The range of years for receipt of the terminal university degree was 1960 to 2006. The mean year of birth was 1955 (SD=9.4), with a range of year of birth from 1933 to 1979. Almost 70 percent (123/177) of respondents were dentists. About 38 percent (68/177) of respondents worked at institutions outside the United States, and 63.6 percent were tenured (77/121).
The mean number of hours worked per week was reported as 46.8 (SD=12.4), with a range of eight to ninety hours. The average self-reported percent time spent in research was 34.6 (SD=29.9) percent, with a range of 0 to 100 percent. One hundred and thirty-seven of 177 respondents (77.4 percent) reported having current funding for their research (working on a funded research project). One hundred eighteen of 177 respondents (66.7 percent) reported having NIDCR funding. Seventy-four percent of the respondents (131/177) reported being a current grant reviewer, 83.1 percent (147/177) reported being a current journal reviewer, and 37.3 percent (66/177) reported currently serving on a journal editorial board.
The mean job satisfaction score was 26.2 (SD=5.34), with a range from 9 to 35, where a higher score indicates greater professional satisfaction. Figure 3⇓ is a frequency distribution of the scores.

Frequency distribution of scores on the professional satisfaction scale as reported by members of the IADR Behavioral Sciences and Health Services Research Group in 2005
Bivariate Analyses
Respondents who reported a greater number of publications were more likely to be male (T=3.1, p=.003) and have received their terminal degree earlier (F=6.75, p=0.10). There was no relationship between productivity and year of birth or whether the individual worked in the United States or another country.
Respondents who reported a greater proportion of their time spent in research also reported more research papers (R=0.25, p=.001). Similarly, greater self-reported productivity in publishing was related to having tenure (T=2.32, p=.022), any current research funding (T=4.35, p=.001), NIDCR current funding (T=2.57, p=.011), serving as a grant reviewer (T=5.02, p=.001), serving as a journal reviewer (T=6.53, p=.001), and serving on an editorial board (T=3.69, p=.001).
Productivity was weakly associated with job satisfaction (R=.157, p=.037). Figure 4⇓ is a plot of this relationship.

Relationship between the score on the job satisfaction scale and number of publications in PubMed journals in the preceding twenty-four months (R=.157, p=.037)
Exploring the Gender Relationship
The mean age of female respondents was five years less than for males (47 [SD=8.9] vs. 52 [SD=9.4] years, respectively; T=3.28, p=.001), and they graduated with their highest degree more recently. The mean year of graduation of female and male respondents was 1991 (SD=0.6) and 1987 (SD=11.3), respectively (T=2.60, p=.010). Women were less likely to be tenured; the proportions of tenured women and men were 48.9 and 72.4 percent, respectively (chi-square=6.73, df=1, p=.009). Gender was unrelated to percent time reported in research. Means were 35.6 percent (SD=30.3) for women and 33.8 percent (SD=29.6) for men (t=.408, p=.68). Gender also was unrelated to funding or service as a reviewer or on editorial boards. There was no gender difference in job satisfaction.
Gender was included in a regression analysis evaluating a model containing both personal and professional characteristics that were related in the bivariate analyses in order to assess which were most important. The only significant predictor of the number of published research articles other than gender was the percent time spent in research (Table 1⇓). Because of the nature of the distribution of the dependent measure, the analysis was repeated using logistic regression in which the dependent measure was bivariate (0=no publications reported or 1=any publications). The result was the same.
Personal and professional characteristics regressed on number of articles in PubMed journals in the preceding twenty-four months for members of the IADR Behavioral Sciences and Health Services Research Group
Discussion
Compared to the dentist researchers investigated in the U.S.-Canadian study,3 the population of dental researchers studied here produced about double the number of published articles, on average 4.9 per year. As with the previous work, 70 percent of respondents were dentists, but this study population had a greater number of years of service. Forty-three percent of the respondents in our study were female, and they had received their terminal degree more recently than the men. The number of hours worked per week was similar to the 2001 population of dental educators studied,4 but the proportion of their time they reported as spent on research was nearly three times as great (around 12 percent in 2001 versus 35 percent in the current study). Seventy-four percent of respondents in the current study reported having research grant support versus about 20 percent in the earlier study.
Gender and time spent in research were the best predictors of research productivity in this accomplished population. There was no difference in time for research between the men and women in our study. Controlling for gender, the best single predictor of research productivity remained percent time spent in research.
In the two earlier studies that addressed gender issues, there were reported differences either stemming from access to time for research or research resources or from perceptions of a less supportive environment. In contrast, in our study, professional satisfaction was high and did not differ between men and women. Thus, the findings from this subset of all dental researchers suggest that the 2001 study that sampled from the ADEA membership list4 excluded a significant number of research-oriented faculty members and that the low response rate of the U.S.-Canadian study3 may have biased the reported findings.
Overall, the members of the IADR group spent almost three times as much time in research and were more than twice as productive as those faculty members described in previous studies. Most were dentists, and three-quarters had external funding for their research. Assuming nonrespondents were less engaged and interested in research, the results may understate these differences in work and work environment. A key limitation of the survey is that it is unclear if the funding results in more protected time for research or vice versa. The previous U.S.-Canadian educator study indicated scholarship. Consequently, dissemination of current research and scientific transfer may be compromised.
Case studies are needed to understand whether institutions should concentrate time and resources among a dedicated coterie of individuals who have research-intensive careers or increase opportunities for faculty members more generally. These data should provide a platform for further discussion of research in our dental schools.
Acknowledgments
We are grateful for support, in part, for this project through Grant No. U54DE14254 from the National Institute of Dental and Craniofacial Research, National Institutes of Health.
Footnotes
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Dr. Milgrom is Professor, Department of Dental Public Health Sciences, School of Dentistry, University of Washington; Dr. Heima is Acting Assistant Professor, Department of Pediatric Dentistry, School of Dentistry, University of Washington; Dr. Tomar is Professor and Chair, Department of Community Dentistry and Behavioral Science, College of Dentistry, University of Florida; and Dr. Kunzel is Associate Professor, Clinical Dental Community, Department of Community Health, College of Dental Medicine, Columbia University. Direct correspondence and requests for reprints to Dr. Peter Milgrom, Department of Dental Public Health Sciences, School of Dentistry, University of Washington, Box 357475, Seattle, WA 98195-7475; 206-685-4183 phone; 206-685-4258 fax; dfrc{at}u.washington.edu.
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This project was supported, in part, by Grant No. U54DE14254 from the National Institute of Dental and Craniofacial Research, National Institutes of Health.
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