The “Global strategy on human resources for health: Workforce 2030” was adopted by the 69th World Health Assembly. Amongst its objectives is the strengthening of data on human resources for health. These data include the course completion and drop-out rates which are important indices that should be of concern to medical education and training institutions, and to WHO Member States, to inform mechanisms that support recruitment and retention.
Aside from the health workforce shortages seen in most countries, worsened by the phenomenon of emigration, course completion and drop-out rates among medical students and students in allied health professions, have significant economic impact. A high drop-out rate can lead to significant economic losses to a country, as the public investments made on the education and training of students before they dropped out, are wasted. Apart from the fact that high drop-out rates may negatively affect the image of the affected institutions, the affected students and their families may suffer psychosocial problems of rejection and reduced self-worth, as well as the opportunity cost and financial investments made in their own studies.
Whereas the education of various cadres of health professionals through existing health educational and training institutions remains a fundamental factor in the development of HRH, there exist limited data on the course completion and drop-out rates of medical students and students in professions allied to medicine. Though this study sought data across health professional and health workforce groups, only data for medical education/ pre-service medical students were obtained. Unlike what was found in the case of New Zealand, Australia, United States of America (USA), and the United Kingdom (UK), with platforms for data collation and tracking of the performance of medical students, this study found a substantial lack of effective and efficient platforms and mechanisms for such data collation in most institutions and countries from which data were sought. Whereas little or no difficulty was experienced in accessing secondary data from New Zealand and Australia , the limited period for this study coupled with the fact that data were not publicly accessible in some countries due to some restrictions and requirements for application for data (sometimes within a narrow window period for application) made it difficult to access secondary data from the United Kingdom Medical Education Database (UKMED) , the database of the Association of American Medical Colleges (AAMC) Student Records System (SRS) , and the database of the Organization for Economic Co-operation and Development (OECD) .
It is apparent from available literature and analyzed data that the course completion and drop-out rates of medical students vary across countries. Data are unavailable to determine whether there is further variation within countries, or within or across occupations. An analysis of publicly available data on pre-service medical students sourced from Medical Deans in New Zealand , between the year 2014 and the year 2020, revealed relatively stable high course completion and low drop-out rates. Similarly, a study of publicly available data on pre-service medical students sourced from Medical Deans in Australia  between the year 2014 and the year 2020 also revealed relatively stable high course completion and low drop-out rates, even though the rates for Australia were relatively more stable than those for medical students in New Zealand. Some drop-out rates are to be expected; this could be due to personal life choices, health reasons, insufficient academic progression or fitness to practice reasons. The reasons for the variations found in the course-completion and drop-out rates among pre-service medical students in New Zealand and Australia are not immediately known. In the United States of America, a study conducted among three (3) cohorts of matriculating classes of medical students and followed up for 10 years each, revealed a relatively high graduation/course completion rate and a low drop-out rate. Among all the medical students across the 3 cohorts, it was reported that only 1.4% of the medical students left medical school . This study finding is similar to the findings in another study on course completion and drop-out rates of US medical students, sourced from the website of the Association of American Medical Colleges (AAMC) Student Records System (SRS) . The AAMC study found that the medical school graduation rates for students undergoing the Doctor of Medicine (MD) medical degree program remained stable from 1993–1994 through 2012–2013, with a 4-year graduation rate that ranged from 81.6 to 83.4% and with a total national attrition rate of 3.3%. It also found that 6 years after matriculation, the average graduation rate was 95.9% for MD students not participating in combined degree programs. This amounts to a drop-out rate of 4.1%. These findings are similar to findings from a 2004 cross-sectional study of students admitted into the College of Medicine, King Saud University, Saudi Arabia. A study of 5 academic years (1994–1998) revealed a low drop-out rate of 3.8% . Similarly, a retrospective descriptive study of medical school attrition over a 10-year period (2001–2011) carried out at the University College Cork, revealed an overall drop-out rate of 5.7% , while another study conducted by Heublein et al.  on drop-out rate among medical students in Germany found a drop-out rate of 10%. Unlike the drop-out rate of about 10.0% and a high course completion rate (about 90.0%) that were found in a comparative study conducted among 5-year undergraduate and 4-year graduate entry medical students who graduated in the year 2007 and 2008 from the University of Nottingham, United Kingdom , a drop-out rate of 14% was found from the result of a retrospective study of records of medical students between 1983 and 1992 at Leeds School of Medicine, United Kingdom . The variation in the UK studies may be due to the varied number of cohorts, categories, and number of medical students that were studied, and different interventions introduced over the time period. A previous study of 396 medical students in Pakistan conducted over a 6-year period (1996–2001), revealed a drop-out rate of 16%. 
While it was difficult to source primary and secondary data from low- and middle-income countries (LMIC) largely due to non-existing institutional platforms for regular collation of such important data, data on medical students from medical schools in Nigeria were sourced through the platform of the Medical and Dental Council of Nigeria (MDCN) which regulates the medical and dental professions in Nigeria . The obtained data revealed a contrast from the data obtained from New Zealand and Australia with an average course completion rate of 88.3%, and an average drop-out rate of 11.7%. When the findings from New Zealand and Australia are compared with the findings from Nigeria, we appreciate the variations in course completion and drop-out rates between countries. In comparison with the rates obtained for New Zealand and Australia, the observed higher drop-out and lower course-completion rates among medical students in Nigeria, particularly in the respective years of 2019 (drop-out rate of 20.8%) and 2020 (drop-out rate of 15.8%) is worthy of further interrogation. The recorded higher drop-out rates may however be attributed to periods of stagnation in some medical schools in Nigeria due to suspension of the accreditation status of some medical schools, disruptions in the academic calendar caused by frequent industrial actions by academic staff of universities, industrial actions by medical doctors and other health workers, as well as disruptions due to the COVID-19 pandemic (particularly during the first wave of COVID-19 in Nigeria in the year 2020) [18,19,20,21,22,23]. The difference in admission policies, duration of study, curriculum, and adopted teaching and training methods may also account for the difference in drop-out rates between the countries  as the traditional type of curriculum is used in Nigeria. Furthermore, as was observed in the literature review done by Arulsamy Anand  on reasons for drop-out in medical schools, other probable reasons for the high drop-out rate may be the lack of motivation and weak academic abilities of some medical students, health challenges, and financial constraints experienced by some medical students (especially those with poor socio-economic backgrounds) worsened by absence of student loans and bursaries. Another factor may be the availability of student welfare services including academic advising and counselling services, as well as the increasing emigration of families from Nigeria to other developed countries, with medical students withdrawing from school to enable them emigrate with their families. [26, 27]
There was great difficulty in accessing data on course completion and drop-out rates from medical educational training institutions/medical schools, essentially due to the virtual non-existence of institutional platforms and mechanisms for such data collation, and in some cases, the restrictions imposed on public access to such data. These significantly limited the data that could be sourced directly in the course of this study. Another limitation was the fact that majority of available literature on course completion and drop-out rates involved studies conducted in high income and developed countries, a fact that made comparative analysis difficult. The non-uniform number and cohort of medical students studied in this paper and in most of the literature found on course completion and drop-out rates, as well as the limited number of countries studied, is a limitation on the generalizability of the study findings. Another limitation was the non-segregation into public and private medical schools in most of the publicly available data. A segregation of the data would have helped to evaluate if there were any variations in the course completion and drop-out rates between public and private medical schools.