Table 2.

Characteristics of each article included in the study.

*Source	Country Source	Sampled Population with N	Perspective Studied	Methods	Outcomes
Abu-Zaid et al. 2014 [54]	Saudi- Arabia	116/171 female medical students	Perceived barriers	-Online, self-rating survey, using Likert scale	-Top three barriers identified: Greater preference for patient care than research (75.0%); Work/life balance (52.6%); and lack of female role models (48.3%).
Abu-Zaid, 2014 [14]	Saudi-Arabia	61 female second year undergraduate medical students	Perceived attitudes	-Cross-sectional, self-rating survey	−31.1% had previous summer research experiences (68.0% local and 33.0% international programs). -All showed positive attitudes towards undergraduate research. - 72.0% endorsed the importance and 44.0% the compulsoriness of integrating scientific research into undergraduate medical education curricula.
Al-Halabi, 2014 [15]	Kuwait	150 sixth and seventh year medical students	Experiences, attitudes, and barriers	-Questionnaire	−66.0% of the students had participated in research. -54.0% students read medical journals regularly. -Barriers included: Lack of time due to other commitments or studies (33.9%), lack of interest either by the participant or other members of his/her project group (27.4%), lack of guidance and supervision (16.1%), lack of encouragement from the project’s mentor (12.1%), and lack of knowledge on how to write a scientific article for publication (10.5%). -42.0% of the students believed that research is important during undergraduate education, while 77.3% believed that it will become important during their future career.
Anbari et al. 2015 [58]	Iran	627 students in six schools of medical sciences	Barriers and infrastructure	-Quantitative and qualitative analytical approaches. - Research vs non-research groups -Barriers were validated using the Delphi technique on 36 students.	- Research students reported institutional barriers such as time, lack of access to electronic resources and prolongation of the process of buying equipment. -Non-research students reported individual barriers including lack of time, scientific writing skills, and access to trained assistants.
Baig, 2013 [33]	Pakistan	398 medical students at four medical universities	Perceptions, Prior experience and future research intent	-Data collection tool using a questionnaire and open-ended questions.	−88% intended to do research prior to medical school but only 51% reported they had previous research experience. -Reasons for engaging in research were to improve curriculum vitae (75%) and increase competitiveness for residency in the USA (43%).
Burgoyne, 2010 [16]	United Kingdom	317 undergraduate medical students	Transferable and research skills, prior research experience, attitude and motivation	-Questionnaire	−81% reported unawareness of opportunities. -51% expressed interest in research career. -56.5% reported moderate motivation, 35.8% high motivation, and 7.7% low motivation. -Barriers included: Isolation from friends (9%), felt like it was overly challenging or uninteresting (13%), undecided (11%).
Carter, 2016 [20]	United States (U.S)	266/346 osteopathic medical students	Research experience, interest during medical school	-Questionnaire	−81% had prior research experience. -75% had interest during medical school. -82% favored clinical research.
de Oliveira et al. 2011 [17]	Brazil	1004 medical students from 13 medical programs	-Availability and degree of involvement -Barriers	-Questionnaire	−7% had no interest in research. - 60% of them were involved in research training. -Barriers: Lack of institutional incentive, defective infrastructure, insufficient time available for professors to mentor undergraduate students.
Ejaz, 2011 [47]	Pakistan	387 final year medical students and fresh graduates	Research involvement, interest and barriers	-Cross-sectional questionnaire	-Medical students results only: 49% conducted literature search, 65% had journal reading experience due to the requirement of their institution. 41% undergraduates had already participated in a research project, however, mostly in the field as data collectors or computer assistants. -Barriers included: Current research status and teachings of Pakistan to be inadequate.
Funston et al. 2016 [48]	United Kingdom (UK)	1625 responses from 38 countries (excluding US); analysis restricted to countries with > 100 responses (n  =  890)	Perceptions	-Online questionnaire	-Less than 50% thought their institution provided adequate research training. -Key barriers were lack of time and mentors. -Females were less interested. -The barriers and satisfaction with research training differed significantly among countries.
Jimmy, 2013 [29]	India	114 medical students	Perception and benefits	-Cross sectional study: Questionnaires	−20.9% had publications. -81.7% saw research being essential to understanding. -38.3% thought it cumbersome. -24.3% of the students were involved in research purely for acquiring knowledge. -18.3% were pursuing interest in research, while 1.7% were doing research to improve their curriculum vitae. -73.9% found it essential for all students to do research. -Barriers found: Lack of time, lack of incentives in the form of scholarships, and post-graduate specialty selection.
Kharraz et al. 2016 [55]	Saudi Arabia	221/350 medical students.	Perceived barriers	-Online, cross-sectional, self-rating survey	-Participation significantly differed by gender (males vs. females): 68.6% vs. 45.4%. -Top three barriers: Lack of time (77.4%), lack of formal courses in curriculum (76%), and lack of UR mentors (70.1%). Others were lack of mentors, lack of interest in research, lack of finding same-gender research mentor, and lack of opportunities.
Kumar, 2009 [40]	India	471 medical students	Awareness, perceptions and practices	-Questionnaire-based qualitative study	−70% were aware about research although the level of awareness varied. -Various skills of conducting research were known to 47% of the students. -76% were part of a research team mainly as a part of the medical curriculum. -8.3% were confident of research as a career option.
Mahmood, 2017 [4]	Pakistan	294 medical students	-Current research practices. -Future intentions. -Related motivations, barriers, and sought-after interventions	-Self-administered questionnaire	-Intentions to pursue research at a professional level remained low (19.7%). -Intentions decreased each passing year of study. -Most commonly expressed motivation for pursuing research was “admission into a residency program” (71.8%). -Such intention was associated with a decreased likelihood of pursing research professionally. -Barriers: Lack of time (72.4%), lack of supervisors (50.3%), lack of opportunity (48.3%).
Meraj, 2016 [34]	Pakistan	172 medical students	Perceptions and attitudes	-Cross-sectional questionnaire	−45.3% were aware of research opportunities. -65.7% thought research was important to future career and relevant to their lives -41.9% not interested in research as a career. -41.3% students enjoyed research -70% perceived research as stressful and 62.2% complex
Mina et al., 2016 [32]	Saudi Arabia	218/350 medical students	Perception and participation	-Online survey	-Top three influential factors: Facilitate entry into competitive residency programs (88.1%), improve curriculum vitae (81.2%), and publish in peer-reviewed journals (79.8%). -Participation in research significantly differed by gender, academic year, and GPA.
Moraes, 2016 [27]	Brazil	278 medical students from first to sixth year.	Interest in research	-Cross-sectional, self-administered questionnaire	−81.7% were interested in research. -Only 4.7% of the students thought research is important. -No statistically significant association with age, gender, number of physicians in their family, prior college courses were found.
Nel et al., 2013 [30]	South Africa	733 medical students	Attitudes	-Cross-sectional survey	−61% had positive attitudes toward research. -74% thought involvement is important -22% voluntarily engaged in research -4% presented at a meeting and 3% had published Perceived barriers: Lack of adequate training, time, and research opportunities.
Oliveira, 2014 [49]	Brazil	415 first through sixth year medical students	Understanding, advantages, difficulties and motivations	-Questionnaire	−47.2% were involved in research. -Main barrier reported was time constraint. -Among students not involved in research, 91.1% reported, however, that they favored its inclusion in the curriculum.
O’ Sullivan, 2009 [50]	United States (U.S)	40 medical students	Attitudes	-Qualitative based on interviews conducted in person at locations chosen by participant.	- Five (5) themes were reported: Early exposure to research, role models and mentoring, career pathways, interplay of personal and social factors, and career support for junior faculty members.
Park et al., 2010 [35]	New Zealand	558 medical students	Attitudes	-Questionnaire	−25% participated in some form of research activity, mostly in the summer, during medical school. -70% expressed interest in participating in research during medical school. -68% of respondents were aware of the intercalated research degree option but only 8.6% were interested. -35% of respondents planned to be involved in research throughout their medical career. -More students rated lifestyle (84% affirmative) and earning potential (43% affirmative) as more important factors than opportunity for research (23% affirmative) when choosing a career specialty.
Pathipati, 2016 [31]	United States (U.S)	328 medical students	Perception of research year	-Online survey at 5 medical schools with highly regarded research programs	-Reasons for research years off: Increase competitiveness for residency application (32%), time to pursue other opportunities (24%), and academic interest (23%). -Students who would still take a research year even if they were already assured a position in a residency program of their choice were at 65%, while 35% would not take a research year.
Rosenkranz, 2015 [18]	Australia	579/806 medical students from first year through fifth year	Attitudes, motivations, and barriers	-Convergent parallel mixed methods study using cross-sectional quantitative survey data and qualitative semi-structured interview findings	−7.5 % of students had prior research experience. -42% indicated interest beyond medical school. -89.1% of students believe conducting research is advantageous for medical career. -44.2% believe bureaucracy surrounding research is a significant deterrent. -49.8% of students were neutral to research and lower salary.
Sheikh, 2013 [59]	Pakistan	122 students	Interest and enthusiasm	-Case (not interested in research)-control (those interested) study	-Barriers identified by interested students: Curriculum overload, internet inexperience, an uncooperative community, difficulty in finding a mentor and selecting a topic, lack of previous exposure, and lack of internet facilities. -Barriers identified by non-interested students: sleep loss, extracurricular activities, uncooperative colleagues, inclement weather (hot and humid), lack of knowledge, bad past experiences, social commitments, drugs/addictions, laziness, uncooperative faculty, transportation problems, lack of motives and incentives, faculty-forced research, fatigue, and an attitude that considered research useless.
Siemens, 2010 [51]	Canada	327 second and fourth year medical students at three medical schools.	Attitudes and experience	-Questionnaire	-Involved in research prior to medical school (87%). -43% were not significantly involved in research during medical school. -24% were not interested. -44% believed research is important in future career. -Barriers included: Time, availability of research mentors, lack of formal teaching of research methodology, and lack of appropriate acknowledgement.
Stockfelt, 2016 [19]	Sweden	471 medical students	Research interest and activity	-Questionnaire administered as a follow up to a 2006 survey	−16% were actively involved in research. -36% were interested. -Barriers to research included: Lack of time (23%), excessive workload (22%), and not enough time to study (16%). -Financial compensation, expansion of research opportunities, and career planning would aid in research interest.

*Brackets denotes the number in the reference list.