Abstract
The purpose of this article is to examine student retention rates and graduation among a doctoral program at a Mid-Atlantic institution. This qualitative study found that faculty encouragement, self-motivation, the cohort model, and the structure of this program contributed to its success. The authors recommend a universal model of retention, as well as a national database of graduate retention rates, be created to aid school administrators in future decision making.
The purpose of this article is to examine retention and graduation rates for doctoral programs. A Mid-Atlantic institution’s doctoral program in education is introduced as an initial case study. This particular doctoral program uses a cohort model, grouping students into separate cadres based on time of initial enrollment. For this study, researchers conducted a series of interviews from four different cohorts in the doctoral program. The initial enrollment year for the four cohorts studied ranged from 1995 to 2004, although the institution continues to enroll and graduate doctoral cohorts. These particular cohorts were studied because of their 100% completion rate. Later in the study, it will be revealed that 7 years was the average completion rate from initial enrollment to graduation. Therefore these cohorts, while initially appearing dated for the purpose of this study do, in fact, have particular relevance. Altogether, 19 respondents provided detailed reflections on their experiences in the program based on a 13-question interview (see Appendix). Once the interviews were completed, the lead researcher analyzed the transcriptions and coded thematic similarities using methods of reduction and interpretation outlined in Smith (2003). Using this technique, the researcher began with specific examples and slowly worked toward more general categorizations.
This qualitative case study could serve as a future model for implementing programmatic structures that yield higher retention and graduation rates for doctoral students while better serving the needs of graduate enrollment managers and the graduate students alike. In addition, this study outlines several graduate student-specific techniques, such as deeper academic engagement, which contributed to stronger graduate student retention and graduation rates. These strategies may prove effective and have universal applications for the improvement of both doctoral retention and graduation rates but undergraduate student retention and graduation rates as well.
The examination of graduate student retention specifically has historically been subordinated to its undergraduate counterpart. Only recently has an effort been made by the National Association of Graduate Enrollment Management, and its members, to pursue the question of retention for graduate students (Connor, LaFave, & Balayan, 2015). An extensive review of literature validates a need for further investigation into graduate student retention rates.
Literature Review
Through strategic enrollment management, which is a comprehensive approach to student support from admissions to graduation, retention efforts support student success as they move to degree conferral (Henderson, 2012). Retention rates of first-year undergraduate students are often viewed as a measure of institutional success in comparison with competing colleges and universities (Duniway, 2012). This is aligned with an accountability imperative to show return on investment for a college education, which places undergraduate retention in the spotlight (Selingo, 2015). Balayan (2015) elaborated on this retention discussion in her study regarding the factors and conditions associated with graduate enrollment management practitioners’ participation in professional development. What is missing from the dialogue, however, is how retention is understood and practiced on the graduate level.
Undergraduate Research Focus
Presently, there is a significant body of literature on undergraduate student retention in comparison to sources on graduate student retention (Carroll, Ng, & Birch, 2013). Conducting a search of ProQuest’s Education Resources Information Center for the terms undergraduate student* (including both singular and plural forms of the word) AND retention yields 646 results from peer-reviewed publications since 2010. By stark contrast, the same search for graduate student retention shows research on this population is scarce. When using all the same search fields and just changing “undergraduate” to “graduate,” the results dwindle to 175 since 2010. The existing sources are often specific case studies on certain populations or settings such as Mendoza, Villareal, and Gunderson (2014) and Carroll et al. (2013). In addition to the scarcity of academic sources, there is no universal model which has been adopted for graduate student retention such as Tinto (2012) developed for undergraduate populations. More than 20 years of undergraduate retention data are captured by the National Center for Education Statistics’ Integrated Postsecondary Education Data System (2015a). Unfortunately, their definition of retention does not include graduate students (National Center for Education Statistics, 2015b). This lack of a national database, a graduate retention model and a definition, coupled with scarce academic resources, establishes the need for further research and a unified model on how to successfully retain graduate students.
On the undergraduate level, academic success, financial aid, student support from faculty and advisors, and genuine learning all contribute to a student’s persistence to graduation (Yale, 2010). Tinto (2012) is the foundational source for retention theory and he consistently noted factors such as academic success and social engagement as determinants of whether a student is retained. While some retention practices developed for undergraduate students may be applicable on the graduate level, there are key differences in the populations and each have unique needs which lead to their retention. When consulted for this study, Tinto offered: Though the issues that shape student success at the undergraduate level are similar to those that influence success at the graduate level, there are important differences that must shape how the model is adapted. First one has to account for the different levels and types of graduate degree programs. Pursuing a doctorate, for instance, is very different than pursuing a master’s degree. But unlike undergraduate study and to a large degree a master’s degree, a student’s experience at the doctoral level tends to be influenced by a relatively few people, most notably one’s doctoral and dissertation advisor. Furthermore, while one can talk about the influence of institutional policies, practices, and culture, at the graduate level, one also needs to focus on departmental or program policies, practices, and culture. (V. Tinto, personal communication, July 8, 2015)
Learning Differences Between Graduate Students and Undergraduates
As Tinto indicated, there is a need for more understanding of how graduate students differ from undergraduates in relation to areas such as student success. As the model is developed, particular attention will need to be paid to factors such as delivery format which may significantly influence less traditional graduate students but not necessarily the traditional undergraduate. One difference is in how these two populations learn. For example, graduate students are often adult learners, who have been found to be self-directed and self-motivated in their approach to learning (Knowles, Holton, & Swanson, 2011). A universal retention model for graduate students, then, would need to include how to foster self-directed learning. Tinto also noted that although both masters and doctoral students are considered graduate students, it is also necessary to distinguish between those two levels when creating a model. Since the purpose of this study was to investigate the retention of a cohort-based doctoral program, it was outside the research scope to identify retention strategies based on the differences between masters and doctoral students. The research findings do reinforce, however, the need for more studies focused on graduate student retention with a specific segmentation between master’s and doctoral level students.
As implied earlier, there is a lack of research determining theories for why doctoral students specifically persist to graduation (Vaquera, 2008). Vaquera (2008) also pointed to variability in retention rates by subject area, size, and other considerations, which can create challenges in developing a universal model. While this all-encompassing model does not exist, there are smaller scale studies resulting in retention theories for this population, such as the cohort program studied by Vaquera. Similar to Tinto’s (2012) model, Vaquera posited doctoral students may be retained by a combination of factors such as quality academics, supportive faculty, and the existence of a strong cohort. It is worth noting, however, that the data and sources for this study were outdated, having been collected in the 1990s. Furthermore, the data were specific only to doctoral students who were in the earlier portion of their programs and only included one Hispanic institution in the southwestern United States. Another reason a graduate student might persist includes the delivery model, specifically if it is an entirely online program (Park, Boman, Dean Care, Edwards, & Perry, 2009). The authors found graduate students enrolled in a distance learning program were more likely to persist to graduation. This may be due to the flexibility and convenience of online learning, coupled with how it aligns with how a graduate adult student learns (Knowles et al., 2011).
Obstacles to Doctoral Student Retention
Hesli, Fink, and Duffy (2003a) conducted a study in a large Midwestern university attempting to flesh out the reasons for graduate student dissatisfaction. Among factors such as economic, social, symbolic, and cultural capital, the most important seemed to be student relationships with their faculty members. The single best predictor of dissatisfaction with the graduate experience is whether the doctoral student receives sufficient encouragement, mentoring, and consultation from faculty. An additional study conducted by Hesli et al. (2003b) examined the reasons behind possible withdrawals. A survey distributed to over 500 graduate students yielded mixed results between genders. Males indicated that problems with the job market, most explicitly the lack of employment opportunities, were most likely to affect continuing their education at the graduate level. Females, on the other hand, cited an unsupportive work environment as chief factor affecting graduate school withdrawal.
The Council of Graduate Schools (2008a, 2008b, 2009, 2010) conducted a 7-year study to investigate PhD completion and attrition. They established six overarching factors that influenced students’ attrition or completion in their PhD program: selection, mentoring, financial support, program environment, research mode of the field, and processes and procedures. Golde (2005) conducted a study of 58 students in four varying disciplines who failed to complete their PhD program. He found six overarching themes that contributed to students’ attrition. The first five themes were associated with incongruence between the student and the program, once again indicating that the fit between students and the academic program is paramount to their success. The sixth theme in Golde’s study was students’ structural isolation. The dissertation writing portion of doctoral degrees can often be a very lonely place for a doctoral student, as they are very often isolated. According to Ali and Kohun (2006), doctoral student isolation often contributes to their attrition.
Doctoral Retention and Graduation Rates Require Attention
Lovitts (2001) indicated that for the last 40 years, the attrition rates of doctoral programs in the United States are approximately 40% to 50%. If this percentage were to be converted into dollars spent by students, and universities, the number would be enormous. It is apparent that a significant proportion of attrition is preventable. In addition, attrition is costly, which further warrants the increasing need for institutions to implement more effective methods of retaining and graduating students.
Golde (2005) suggested that these rates differ among programs, departments, colleges, and universities. Golde also provided three reasons why doctoral student attrition should be researched and those reasons include researchers cannot currently explain the low doctoral graduation rates, high attrition may be a university or societal issue, and the economic and human capital costs related to high attrition (low retention) rates are significant.
Recent publications by NAGAP members have initiated discussion on graduate student retention rates. Connor et al. (2015) concluded from a 2013 survey of graduate enrollment management professionals that little time is spent on retaining graduate students once admitted. They advocated for an integrated system that reinforces student support throughout their entire “life cycle,” thereby ensuring greater retention and higher graduation rates. McConnell (2015) wrote an article in a NAGAP news magazine on graduate student retention focusing on the admission of students. She asked whether recruiters are “being faced with the ethical challenge of enrolling students who will succeed rather than accepting students in order to meet enrollment revenue goals” (p.14). These goals focus specifically on data such as headcount and credit hours. Therefore, student retention may become a peripheral goal to the central aim of ever-increasing enrollment (McConnell, 2015).
The Effectiveness of the Cohort
Because this case study examines a doctoral program utilizing a cohort model, a brief review of the efficacy of the cohort system in other programs is relevant. A cohort consists of a group of students placed together at the beginning of their enrollment. These students remain grouped together until their graduation. California Lutheran University began organizing its MBA students into cohorts in 2006 (Alexander, Kohnke, & Naginey, 2009). The resulting retention data are significant, since the program retained between 65% and 80% of its students in a 3-year period from 2006 to 2008. The cohort method of delivery never reached an attrition rate above 5%. Another study conducted by Beachboard, Beachboard, Li, and Adkinson (2011) also found a statistically significant advantage for graduate programs organized in the cohort model. Theoretically basing their work on Ryan and Deci’s self-determination theory, Beachboard et al. (2011) argued that the cohort model enables increased “relatedness” to peers and faculty and generally greater educational outcomes. The cohort model gives students a better opportunity to define their relationship between faculty and peers on a greater level than other formats. Golde (2005) studied reasons that contributed to doctoral isolation and found that the cohort model positively influenced student persistence to graduation. One example of how the program accomplished this was by taking the cohort on a retreat during their first term. This retreat encouraged students to get to know each other on both a social and academic level, thus creating a sense of community. This retreat also allowed students to interact with faculty and thereby initiated the mentoring process.
In sum, there are some small-scale scholarly publications on graduate student retention, but existing sources do not seem to reflect an overarching model for best practices. Therefore, this article serves as a call to action to develop a universal model and national database of aggregate data on graduate student retention.
Method
The Doctoral Program
Demographics of All Students in the Four Sample Cohorts.
Average time to completion total is not an average of averages but an aggregate average.
Demographics of Respondents in the Four Sample Cohorts.
Since its first cohort in 1995, this doctoral program graduated an average of 87% of its students in total. In addition, 4 of its first 10 cohorts graduated 100% of its enrollees, amounting to a total of 65 conferred doctorates. Because this particular doctoral program was so successful at retaining and graduating its students, it can serve as a case study for graduate retention. This study chose to interview students from those four cohorts which achieved a 100% graduation rate. Altogether, 19 graduates across four cohorts participated in the data collection. Interviews were conducted either over the phone or via email. Responses varied in terms of length, however, phone interviews generally tended to yield more substantive results than email responses. An email interview approach allowed respondents the time to produce thoughtful answers while phone interviews tended to generate a conversational flow, which did not afford the extended reflection time that a typed email response may permit. The researchers noted that the phone interview responses were more immediate and spontaneous. While the researchers did not classify one interview approach as categorically better than the other, it is recommended that future researchers use one consistent interview method.
As noted previously, many of these individuals held executive administration positions, so this study attempted to make the interview process as flexible as possible in order to encourage more participation. Thus, a case study methodology was chosen because it “allows investigators to retain the holistic and meaningful characteristics of real-life events—such as individual life cycles, organizational and managerial process, etc.” (Yin, 2003, p.2). A set of interview questions was drafted for students in the aforementioned four cohorts with 100% graduation rates. These questions attempted to elicit those meaningful characteristics from the perspectives of those actually involved. The faculty of this program maintained a contact list for members of each cohort on the program website. With the permission of the faculty, the researchers utilized this contact list to begin conducting the interviews. Each interviewer corresponded with these graduates either over phone or via email using this contact list. Graduates were informed that their personal information and any identifiers would remain anonymous, but that the results of this study would be subsequently published. Participation in the study provided implied consent as graduates were free to decline participation by not responding to emails or phone calls.
The Interview
The interview itself consisted of 13 questions. Informed by the literature review, researchers asked questions pertaining to their experience within the program. Focusing on peer and faculty relationship and personal motivations, the interview process was designed to elicit the program’s successes from a student perspective. The investigators looked for responses from former students that would present their own perspectives on the program’s structure, peer and faculty relationships, and other factors.
Analysis and Interpretation
After the interviews were completed, the lead researcher analyzed the interview transcripts using the methods outlined in Smith (2003). Based fundamentally on interpretive phenomenology, the researcher obtained the meanings and themes through a “sustained engagement with the text and a process of interpretation” (Smith, 2003, p.66). Response frequency was also considered because if a majority of respondents reached the same conclusions independently, then it is assumed that theme or factor to be equally significant. A list of interview questions can be found in the Appendix. After reading through the transcripts and highlighting significant points of emphasis based on the responses, the researcher found three significant themes among the interview responses. These contributing factors to both student retention and graduation include intrinsic motivation, programmatic structure, and the cohort model. What follows is a discussion of these factors from the perspective of the interviewees.
Intrinsic and Extrinsic Motivation
All 19 respondents clearly recalled that they were motivated to enroll and complete the program for personal or professional reasons. Earning a doctorate enabled them to advance their careers or satisfied a personal long-term goal. For several respondents, earning a doctorate had additional extrinsic motivation since their current contract stipulated that they earn a terminal degree within a set timeframe. Often, many respondents combined the professional goal of upward mobility as a component of the personal goal of higher pay or higher positions. In the context of education, earning a terminal degree, as one respondent suggests, offered “validation” of one’s current position and opened up additional opportunities (Cohort A, Interview 1, personal communication, January 28, 2015). In addition, because many respondents said it was part of a personal goal as well, it suggested that the doctorate carries with it a certain amount of social capital. The personal and professional benefits of completion were intrinsic motivations which contributed to the high retention and graduation rates of this program. However, on a structural level, the program provided students with ample means of achieving these goals.
Programmatic Structure
Coupled with intrinsic personal and professional motivations, the structure of the program also contributed to the high retention rates. Indeed, several respondents were initially drawn to the program because of its cohort format and weekend-only courses. “[T]he arrangement of the class—five weekends in a semester and Fridays and Saturdays [was] doable,” said one respondent (Cohort B, Interview 1, personal communication, January 26, 2015). Another said that, “I knew the program was a quality one because many people were raving about the cohort structure” (Cohort C, Interview 1, personal communication, January 23, 2015). In addition, students in this program completed coursework with at least three rough draft chapters of their dissertation, putting them in an advantageous position upon entering the dissertation phase of the program.
One of the questions from the interview protocol asked respondents to provide three contributing factors to their graduate success. Twelve of the 19 respondents explicitly pointed to the cohort as one of those contributing factors. As previously noted in the literature review, the cohort model statistically leads to better retention rates. When juxtaposed with the responses from students who have actually completed a program with the cohort structure, a stronger relationship between the cohort model and higher retention rates can be drawn. The greatest strength of this cohort format as evidenced by this study’s results is its ability to foster both supportive and competitive relationships among peers.
The Cohort Model
The cohort model engenders friendly competition between students—one that both enhances the learning experience and builds stronger interpersonal relationships. As seen in this study, a healthy, competitive cohort encourages students to participate earnestly and produce better work. Coursework often involved group projects and the expectations for both individual students and the group as a whole were high. As one respondent said, “I didn’t want to let them down” (Cohort B, Interview 2, personal communication, January 23, 2015). In addition, many respondents still maintain relationships with members in their cohort. “We are still connected. I can call them and pick up right where we left off. [We are] Friends for life” (Cohort B, Interview 3, personal communication, January 27, 2015). Because many of these students commuted from across the region, members of the same cohort would carpool, dine, attend class, and spend free time together. “We basically became a family. Everyone wanted to share and help each other out” (Cohort D, Interview 1, personal communication, March 19, 2015). One respondent believes that this supportive atmosphere was the primary reason for persistence to graduation.
Not only did the cohort model foster strong peer-to-peer relationships, it also allowed student–faculty relationships to form. Many respondents mentioned specific professors as very approachable and willing to help students succeed. One respondent indicated that the faculty “would answer me and be very responsive to questions and concerns and even meet with us prior to course meetings” (Cohort B, Interview 4, personal communication, January 23, 2015). In addition, respondents suggested that the faculty themselves were heavily invested in the success of the students. “When you see [faculty members] putting in the time and effort to help you as a student—you don’t want to be a disappointment to them,” said one respondent (Cohort B, Interview 4, personal communication, January 23, 2015). Twelve of the nineteen respondents placed faculty encouragement and support among their three reasons for completion. One respondent remarked, “[t]hey were the best faculty I have ever worked with. They cared, treated us like professionals” (Cohort A, Interview 2, personal communication, January 25, 2015). An approachable, engaging faculty provides students with a foundation to support them throughout their coursework and carries over into the dissertation phase. With this particular program, the faculty were personally and professionally invested in the success of their students according to the respondents.
Thematic Analysis of Doctoral Retention.
Discussion and Conclusion
Because this doctoral program achieved a very successful rate of retention and graduation, it was chosen in an attempt to examine the underlying reasons for its success. Three components—personal motivation, faculty support, and the cohort model—contributed chiefly to the success of the individual students and the program as a whole. However, now that a discussion on doctoral student retention rates has been initiated, it is recommended that institutions begin to systematically gather and share retention data at the graduate level toward a growing body of literature and an aggregate database. It is also recommended that a universal doctoral retention and graduation model be developed.
Current trends suggest that graduate and doctoral enrollment will only increase. According to the U.S. Bureau of Labor Statistics (2015), jobs requiring master’s degrees for entry are predicted to grow by 18.4% from 2012 to 2022. Jobs requiring a doctoral or professional degree will increase by 16% from 2012 to 2022. This increased need for employees to hold postbaccalaureate degrees will in turn increase the potential number of graduate students attending U.S. higher educational institutions. With this in mind, it is imperative universities take a proactive approach to doctoral and graduate retention and graduation.
The program studied in this case study excelled in many of the areas deemed important by the Council of Graduate Schools. It is evident by the high graduation rate that the program selected students who were the appropriate fit for their program. By excelling in the “selection” category, as defined by the Council of Graduate Schools (2008a, 2008b, 2009, 2010), students were not only academically appropriate for the program but also likely to succeed in the environment. Both intrinsic and extrinsic factors motivated students in this case study to first enroll in the program, with many participants combining the professional goal of upward mobility as a component of the personal goal of higher pay, as shown in this study’s results.
The sixth theme in Golde’s (2005) study, regarding reasons that contribute to doctoral attrition, was students’ structural isolation. The Mid-Atlantic program in this study admitted students into a cohort and students took courses together as a cohort during their entire doctoral program. Not only were they labeled a cohort, but the program created an environment that resulted in the students becoming a cohesive group. Many faculty look at mentoring as an additional task to their regular job duties. The program studied integrated mentoring into the program culture, so faculty knew it was an expectation. The cohort model encouraged the program mentoring network to include both advisor–advisee mentoring and peer-to-peer mentoring relationships. This generated a support structure that many students indicated significantly impacted their ability and motivation to complete their doctoral program.
Personal motivation, faculty support, and the cohort model were found to be major themes in this study that influenced the retention rate in the doctoral program. These findings are very much aligned with the literature and indicate that attrition may often be avoidable. Graduate institutions should focus attention on creating cohorts of students who are not only academically suitable but are also a good fit for their program. Furthermore, programs need to foster an environment that mitigates isolation of students and instead creates a network of mentors, both peer-to-peer and faculty-to-student.
Implications to Practice
The results of this case study, coupled with previous studies and a literature review, have significant implications to doctoral graduate programs and in higher educational institutions. As the literature and this case study suggest, three components, personal motivation, faculty support, and the cohort model, were found to be the predominant contributors to the success of individual students and the program as a whole. These results indicate that programs should not only consider admitting motivated students as a cohort but furthermore create a culture within the program that fosters mentoring and inclusiveness.
With the rising costs of graduate education, the retention question is related to social and moral issues. When programs do not effectively retain students, those students still have financial obligations to the university or creditors. Also, the lack of further education may lead to underemployment or even unemployment. In addition to the opportunity and financial cost to a student who fails to complete a doctoral program, there are also substantial institutional costs associated with doctoral students who do not graduate. Furthermore, there are opportunity costs to the institution or program, in the form of time and effort afforded to the student for research, and so forth. “Forty years of studies suggest the long-term attrition rate nationwide is about 50 percent” (Lovitts & Nelson, 2000, p.45). Many graduate students research and select graduate programs based on the U.S. News & World Report (Sweitzer, & Volkwein, 2009). Graduation rates are often used as a measure, along with other factors such as cost and faculty involvement, to rank institutions. It would be unwise for universities and policy makers to ignore the impact of graduation rates and attrition. As more and more students pursue graduate education, the graduate schools and their personnel across the country must begin to formulate retention plans. A national database of aggregate data on graduate student retention would be the first step in aiding colleges and universities in their pursuit of similar retention success as documented by this case study’s doctoral program.
In the interim, until a database is created that would allow for more in-depth and longitudinal studies, there are three key steps programs can take to mitigate attrition: admit students who are motivated and are a good fit for the program, create a program culture where faculty members are committed to mentoring graduate students in addition to teaching or conducting research, and implement a cohort model. In addition, there is still a need for further research on the subject of graduate retention. This particular study focused on a cohort-based doctoral program. However, noncohort based doctoral programs, cohort and noncohort based master’s programs all require attention from researchers. For future inquiries, retention scholars should investigate these previously overlooked populations.
Lovitts & Nelson (2000) found graduate students who felt part of the program and community were more likely to complete the program. Doctoral programs need to invest time into admitting students who are both academically suitable and an appropriate fit with the program’s culture. It is also evident that it is important to use a cohort model. Additionally, increased faculty involvement both in and out of the classroom is vital. Institutions must invest in doctoral mentoring training for faculty, in order to create an inviting environment in which graduate students can succeed and persist to graduation. The individual, educational, societal, and economic results of this investment would be significant as demonstrated by this manuscript.
Appendix
Student Interview Question List
Interviews were conducted by the authors in January of 2015.
What year did you earn your doctorate? How many years were you enrolled in the doctoral program? (Looking for # of years it took to complete.) What were your primary motivators for pursuing a graduate degree? (For example: credentials were required for job, career advancement, increasing earning potential, personal goal, broaden career opportunities, switching careers, and other.) Please explain. What key characteristics led you to select this program over others? (For example, program format, location, cost, financial aid, assistantship opportunities, school or program reputation, faculty, delivery method [in-person, online, hybrid], and recommendation from others.) Please explain. How many students (approximately) were in your cohort? Do you recall what the admissions criteria were when you applied? Did the faculty within your program maintain an encouraging and supportive academic environment? If so, how? If not, why not? Were you able to develop collaborative relationships with faculty in the program? If so, how? If not, why not? How did faculty emphasize scholarship and research within your graduate program? Do you think it was a factor in your graduation? Were you able to develop collaborative relationships with your peers within the program? If so, how? If not, why not? How did the structure and the rigor of the curriculum contribute to your academic success? What three factors most contributed to your persistence and subsequent graduation? (For example, academic advising, mentorship, tutoring, faculty advisement, peer cohort, availability of faculty, availability of administrators, student organizations, etc.) Please explain. Are you employed in a field related to your doctorate? Do you feel that the doctorate has contributed to your professional success? How long did it take to realize a return on the doctoral degree investment? Is there anything else you’d like to mention which made your cohort successful which I haven’t asked about?
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.