Doctor of Philosophy



Doctor of Philosophy, abbreviated as PhD, Ph.D., DPhil or D.Phil. (for the Latin philosophiae doctor or doctor philosophiae), in English-speaking countries, abbreviated as Dr. Phil. or similar in several other countries, is a postgraduate academic degree awarded by universities. The academic level of degrees known as doctorates of philosophy varies considerably according to the country, institution and time period, from entry-level research degrees to higher doctorates.

The term "philosophy" does not refer solely to the modern field of philosophy, but is used in a broader sense in accordance with its original Greek meaning, which is "love of wisdom." In most of Europe, all fields other than theology, law and medicine were traditionally known as philosophy.

The doctorate of philosophy as it exists today originated as a doctorate in the liberal arts at the Humboldt University, and was eventually adopted by American universities, becoming common in large parts of the world in the 20th century. In many countries, the doctorate of philosophy is still awarded only in the liberal arts (known as "philosophy" in continental Europe, hence the name of the degree).

History
The doctorate was extended to philosophy in the European universities in the Middle Ages. At that time all academic disciplines, the first Doctor of Philosophy degree was awarded in Paris in 1150, but the degree did not acquire its modern status as an advanced research degree until the early nineteenth century, following the practice in Germany. Prior to the nineteenth century, professional doctoral degrees could only be awarded in theology, law, or medicine. In 1861, Yale University adopted the German practice (first introduced in the 19th century at the Humboldt University of Berlin) of granting the degree, abbreviated as Dr. phil., to younger students who had completed a prescribed course of graduate study and successfully defended a thesis/dissertation containing original research in science or in the humanities.

From the United States, the degree spread to Canada in 1900, and then to the United Kingdom in 1917. This displaced the existing Doctor of Philosophy degree in some universities; for instance, the DPhil (higher doctorate in the faculty of philosophy) at the University of St Andrews was discontinued and replaced with the Ph.D., (research doctorate). Oxford retained the DPhil abbreviation for their research degrees. Some newer UK universities, for example Buckingham (est. 1976), Sussex (est. 1961), and, until a few years ago, York (est. 1963), chose to adopt the DPhil, as did some universities in New Zealand.

Requirements
The detailed requirements for award of a Ph.D. degree vary throughout the world and even from school to school. In some schools in the US, Canada and Denmark, for example, many universities require coursework in addition to research for Ph.D. degrees. In other countries (such as the UK) there is generally no such condition. It is not uncommon, however, for individual universities or departments to specify additional requirements for students not already in possession of a bachelor's degree or equivalent or higher.

In schools requiring coursework there is sometimes a prescribed minimum amount of study — typically two to three years full time, or a set number of credit hours — which must take place before submission of a thesis. This requirement is sometimes waived for those submitting a portfolio of peer-reviewed published work. The candidate may also be required to successfully complete a certain number of additional, advanced courses relevant to his or her area of specialization.

A candidate must submit a project or thesis or dissertation often consisting of a body of original academic research, which is in principle worthy of publication in a peer-refereed context. In many countries a candidate must defend this work before a panel of expert examiners appointed by the university; in other countries, the dissertation is examined by a panel of expert examiners who stipulate whether the dissertation is in principle passable and the issues that need to be addressed before the dissertation can be passed.

Some universities in the non-English-speaking world have begun adopting similar standards to those of the Anglophone PhD degree for their research doctorates (see the Bologna process).

A Ph.D. student or candidate (abbreviated to Ph.D.c) is conventionally required to study on campus under close supervision. With the popularity of distance education and e-learning technologies, some universities now accept students enrolled into a distance education part-time mode.

Value and criticisms
The Economist published an article citing various criticisms against the state of PhDs. Richard B. Freeman explains that, based on pre-2000 data, at most only 20% of life science PhD students end up getting jobs specifically in research. Only in the fastest developing countries (e.g. China or Brazil) is there a shortage of PhDs. Higher education systems often offer little incentive to move students through PhD programs quickly (and may even provide incentive to slow them down). Germany is one of the few nations engaging these issues, and it has been doing so by reconceptualizing PhD programs to be training for careers, outside of academia, but still at high-level positions. Mark C. Taylor opines that total reform of PhD programs in almost every field is necessary in the U.S., and that pressure to make the necessary changes will need to come from many sources (students, administrators, public and private sectors, etc.). These issues and others are discussed in an April 2011 issue of the journal Nature.

In Canada, where the overflow of PhD degree holders is not as severe, 80% of postdoctoral research fellows end up earning less than or equal to the average construction worker (roughly $38,000 a year). The idea that PhDs are offering little return on investment, monetarily, is bolstered by evidence published in the Journal of Higher Education Management and Policy. Bernard H. Casey suggests that, over all subjects, PhD has an earnings premium of 26%, but notes that masters degrees provide a premium of 23% already. Casey thinks there are significant benefits to society for the extra research training, but points out that this does not change the fact that many individuals could have secured an almost identical salary far earlier (which adds an opportunity cost). Some research suggests that overqualified workers are often less satisfied and less productive at their jobs.

Not all students, however, are motivated to pursue the PhD by hopes of monetary rewards. Some are driven by the desire for further education beyond the undergraduate level, scientific and humanistic curiosity, the desire to contribute to the academic community, service to others, or personal development.

Admission
In Argentina, the admission to a PhD program at an Argentine University requires the full completion of a Master's degree or a Licentiate's degree. Non-Argentinian Master's titles are generally accepted into a PhD program when the degree comes from a recognized university.

Funding
While a significant portion of postgraduate students finance their tuition and living costs with teaching or research work at private and state-run institutions, international institutions, such as the Fullbright Program and the Organization of American States (OAS), have been known to grant full scholarships for tuition with apportions for housing.

Requirements for completion
Upon completion of at least two years' research and course work as a graduate student, a candidate must demonstrate truthful and original contributions to his or her specific field of knowledge within a frame of academic excellence. The doctoral candidate's work should be presented in a dissertation or thesis prepared under the supervision of a tutor or director, and reviewed by a Doctoral Committee. This Committee should be composed of examiners that are external to the program, and at least one of them should also be external to the institution. The academic degree of Doctor, respective to the correspondent field of science that the candidate has contributed with original and rigorous research, is received after a successful defense of the candidate’s dissertation.

Admission
Admission to a PhD program within Australia requires a Masters degree or a Bachelors honours degree (first or second class, upper division), or equivalent, and demonstrated capacity to undertake significant research in the proposed doctoral field.

Framework for Best Practice in Doctoral Research Education in Australia

Scholarships
PhD students are sometimes offered a scholarship to study for their PhD degree. The most common of these in Australia is the government-funded Australian Postgraduate Award (APA), which provides a living stipend to students of approximately A$ 22,500 a year (tax free). APAs are paid for a duration of 3 years, while a 6 month extension is usually possible upon citing delays out of the control of the student. Some universities also fund a similar scholarship that matches the APA amount. In recent years, with the tightening of research funding in Australia, these scholarships have become increasingly hard to obtain. However, APAs have become less competitive as the number of scholarships were to be doubled by 2012. Due to a continual increase in living costs, many PhD students are forced to live under the poverty line. In addition to the more common APA and University scholarships, Australian students have other sources of scholarship funding, with options listed on the JASON Postgraduate Scholarship Database.

Fees
Australian citizens and other eligible PhD and Research Masters students in Australia are generally not charged course fees as these are paid for by the Australian Government under the Research Training Scheme International students and Coursework Masters students must pay course fees, unless they receive a scholarship to cover them.

Requirements for completion
Completion requirements vary. Most Australian PhD programs do not have a required coursework component. The 72 credit points attached to the degree are all in the product of the research, which has to make a significant new contribution to the field. The PhD research product is sent to external examiners, experts in the field of research, who have not been involved in the work. In Australia a formal oral defense is generally not part of the doctoral examination (largely because of the distances that would need to be traveled by the overseas examiners). Examiners are nominated by the candidate's University (often by the Head of Department or Research Office), and their identities are often not officially revealed to the candidate until the examination is complete. Many New Zealand Universities have retained the oral examination requirement, but often external examiner's report is presented by one of the internal examiners. The Australasian Digital Theses Program provided access to PhDs produced recently, as there are generally automatically digitalised and added to this database available from http://adt.caul.edu.au/. As of March 2011, the site is being decommissioned.

Admission
Admission to a PhD program at a Canadian university usually requires completion of a Master's degree in a related field, with sufficiently high grades and proven research ability. In some cases, a student may progress directly from an Honours Bachelor's degree to a PhD program; other programs allow a student to fast-track to a doctoral program after one year of outstanding work in a Master's program (without having to complete the Master's).

An application package typically includes a research proposal, letters of reference, transcripts, and in some cases, a writing sample or GRE scores. A common criterion for prospective PhD students is the comprehensive or qualifying examination, a process that often commences in the second year of a graduate program. Generally, successful completion of the qualifying exam permits continuance in the graduate program. Formats for this examination include oral examination by the student's faculty committee (or a separate qualifying committee), or written tests designed to demonstrate the student's knowledge in a specialized area (see below) or both.

At English-speaking universities, a student may also be required to demonstrate English language abilities, usually by achieving an acceptable score on a standard examination (e.g., Test of English as a Foreign Language (TOEFL)). Depending on the field, the student may also be required to demonstrate ability in one or more additional languages. A prospective student applying to French-speaking universities may also have to demonstrate some English language ability.

Funding
While some students work outside the university (or at student jobs within the university), in some programs students are advised (or must agree) not to devote more than ten hours per week to activities (e.g., employment) outside of their studies, particularly if they have been given funding. For large and prestigious scholarships, such as those from NSERC, this is an absolute requirement.

At some Canadian universities, most PhD students receive an award equivalent to the tuition amount for the first four years (this is sometimes called a tuition deferral or tuition waiver). Other sources of funding include teaching assistantships and research assistantships; experience as a teaching assistant is encouraged but not requisite in many programs. Some programs may require all PhD candidates to teach, which may be done under the supervision of their supervisor or regular faculty. Besides these sources of funding, there are also various competitive scholarships, bursaries, and awards available, such as those offered by the federal government via NSERC, CIHR, or SSHRC.

Requirements for completion
In general, the first two years of study are devoted to completion of coursework and the comprehensive examinations. At this stage, the student is known as a "PhD student" or "doctoral student". It is usually expected that the student will have completed most of his or her required coursework by the end of this stage. Furthermore, it is usually required that by the end of eighteen to thirty-six months after the first registration, the student will have successfully completed the comprehensive exams.

Upon successful completion of the comprehensive exams, the student becomes known as a "PhD candidate". From this stage on, the bulk of the student's time will be devoted to his or her own research, culminating in the completion of a PhD thesis or dissertation. The final requirement is an oral defense of the thesis, which is open to the public in some, but not all, universities. At most Canadian universities, the time needed to complete a PhD degree typically ranges from four to six years. It is, however, not uncommon for students to be unable to complete all the requirements within six years, particularly given that funding packages often support students for only two to four years; many departments will allow program extensions at the discretion of the thesis supervisor and/or department chair. Alternate arrangements exist whereby a student is allowed to let their registration in the program lapse at the end of six years and re-register once the thesis is completed in draft form. The general rule is that graduate students are obligated to pay tuition until the initial thesis submission has been received by the thesis office. In other words, if a PhD student defers or delays the initial submission of their thesis they remain obligated to pay fees until such time that the thesis has been received in good standing.

Denmark and Norway
Denmark and Norway were some of the first countries to introduce the Doctor of Philosophy degree, inspired by the German university system, in 1824. The degree was written as Doctor Philosophiae, abbreviated Dr. Phil. or Dr. Philos. The two countries' systems of higher education were more or less identical at that time; following the dissolution of Denmark-Norway in 1814, the only university of Norway (the Royal Frederick University) nonetheless followed the regulations of the only university of Denmark (and for centuries the only university of both countries), the University of Copenhagen, for several years.

The Dr. Phil. degree was used for all other fields than theology, law and medicine, which had separate degrees: doctor theologiae, doctor juris and doctor medicinae. In the 20th century new degrees were created in the fields of natural sciences, humanities and social sciences, but it was still possible to obtain the Dr. Phil. degree in any field. Most people who started at a doctoral degree had already studied for six or seven years and obtained a Candidate degree (six years) or a Magister degree (seven years), sometimes a Licentiate (a "smaller doctorate"). The former were considered entry-level degrees required before finding permanent employment as a researcher, while the Dr. Phil. degree was often obtained by people who were already well established academics, sometimes even full professors.

Following reforms in the late 1990s and early 2000s, both countries introduced a new Doctor of Philosophy degree, based upon the American PhD and written as Philosophiae Doctor (PhD). In Norway the PhD replaced all other doctoral degrees except Dr. Philos., while in Denmark, the traditional doctorates are still awarded. In Norway the new PhD and the Dr. Philos. are equivalent. In Denmark, the original Dr. Phil. degree is today considered a higher doctorate, as opposed to the PhD, which is considered a "smaller doctorate" at the same level as the former Licentiate. Unlike the PhD, the Dr. Phil. degree is not a supervised degree, does not include any coursework and requires a much larger degree of independent research in both countries.

Admission
Students pursuing the PhD degree must first complete a Master's degree program, which takes two years after graduation with a Bachelor's degree (five years in total). The candidate must find funding and a formal doctoral advisor (Directeur de thèse) with an habilitation throughout the doctoral program.

In France, the Masters program is divided into two branches: "master professionnel", which orientates the students towards the working world, and Master of Research (Master-recherche), which is oriented towards research. The PhD admission is granted by a graduate school (in French, "école doctorale"). A PhD Student has to follow some courses offered by the graduate school while continuing his/her research at laboratory. His/her research may be carried out in a laboratory, at a university, or in a company. In the last case, the company hires the student as an engineer and the student is supervised by both the company's tutor and a labs' professor. The validation of the PhD degree requires generally 3 to 4 years after the Master degree. Consequently, the PhD degree is considered in France as a "Bac +8" diploma. "Bac" stands for Baccalauréat which is the French High-school diploma.

Funding
The financing of PhD studies comes mainly from funds for research of the French Ministry of Higher Education and Research. The most common procedure is a short-term employment contract called doctoral contract : the institution of higher education is the employer and the PhD candidate the employee. However, the student can apply for funds from a company who can host him/her at its premise (as in the case where PhD students do their research in a company). Many other resources come from some regional/city projects, some associations, etc.

Admission
In India, a Masters degree is required to gain admission to a doctoral program. In some subjects, doing a Masters in Philosophy (M.Phil) is a prerequisite to start PhD. For some prestigious universities it is required to qualify the all India level examination such as ‘National Eligibility Test for Lectureship (NET) conducted by ‘University Grants Commission'.

In last few years, there have been many changes in the rules related to PhD in India. According to the new rules, most universities conduct entrance exams in general ability and the selected subject. After clearing these tests, the short-listed candidates need to appear for interview by the available supervisor / guide. The students are required to give presentations of the proposal at the beginning, need to submit progress reports, give pre-submission presentation and finally defend the thesis in an open defence viva voce. Some departments make it mandatory to have one of the examiners to be from US or Europe.

Admission
In Germany an advanced degree (Master, Diploma, Magister or Staatsexamen) and above-average grades are often required to gain admission to a doctoral program. The degree should usually be in a related field. The candidate must also find a tenured professor or Privatdozent to serve as the formal advisor and supervisor (Betreuer) of the dissertation throughout the doctoral program. This supervisor is informally referred to as Doktorvater/Doktormutter (literally 'doctor's father/mother').

Doctoral programs in Germany generally take one to four years – usually three, up to five in engineering – to complete, strongly depending on the subject. There are usually no formal classes or lectures to attend, and the doctoral candidate (Doktorand/-in) mainly conducts independent research under the tutelage of a single professor or advisory committee.

Many doctoral candidates work as teaching or research assistants and are thus actually doing most of the research and teaching activities at their home institutions, but are not paid a reasonably competitive salary for that (in most cases, only a half position is granted). However, external funding by research organisations and foundations is also common. Furthermore, many universities have established research-intensive Graduiertenkollegs, which are graduate schools that provide funding for doctoral theses.

Other countries
In German-speaking countries, most Eastern European countries, the former Soviet Union, most parts of Africa, Asia, and many Spanish-speaking countries the corresponding degree is simply called "doctor" (Doktor), and is distinguished by subject area with a Latin suffix (e.g. "Dr. med." for doctor medicinae, "Dr. rer. nat." for doctor rerum naturalium — Doctor of Natural Science, "Dr. phil." for doctor philosophiae, "Dr. iur." for doctor iuris, etc.).

In the former Soviet Union, the Doctor of Sciences is the higher of two sequential post-graduate degrees, with Candidate of Sciences (Russian – кандидат наук) being universally accepted as the equivalent of the PhD, while the Doctorate is a (Full) Professors' or Academicians' separate and subsequent degree, indicating that the holder is a distinguished, honoured, and outstanding member of the scientific community. It is rarely awarded to those younger than late middle age or lacking in achievement and is a symbol of success in an academic career.

Italy
The Dottorato di ricerca (research doctorate), abbreviated to "Dott. Ric." or "Ph.D.", is an academic title awarded at the end of a course of not less than three years, admission to which is based on entrance examinations. In case of MD/PhD the Ph.D. programme may last only two years.

Doctorate courses are open, without age or citizenship limits, to all those who already hold a "laurea magistrale" (master degree) or similar academic title awarded abroad which has been recognised as equivalent to an Italian degree by the Committee responsible for the entrance examinations.

The number of places on offer each year and details of the entrance examinations are set out in the examination announcement.

Poland
A doctor's degree (pl. Doktor), abbreviated to Phd (pl. dr) is an advanced academic degree awarded by universities in most fields    as well as by the Polish Academy of Sciences, regulated by the Polish parliament acts and the government orders, in particular by the Ministry of Science and Higher Education of the Republic of Poland. Commonly, students with a master's degree or equivalent are accepted to a doctoral entrance exam. The title of Phd is awarded to a scientist who 1) completed a minimum of 3 years of Phd studies (pl. studia doktoranckie), 2) finished his/her theoretical and/or laboratory’s scientific work, 3) passed all Phd examinations, 4) submitted his/her dissertation- a document presenting the author's research and findings, 5) successfully defended his/her doctoral thesis. Typically, upon completion, the candidate undergoes an oral examination, always public, by his/her supervisory committee with expertise in the given discipline.

Scandinavia
The doctorate was introduced in Denmark-Norway in 1479 and awarded in theology, law and medicine, while the Magister's degree was the highest degree at the Faculty of Philosophy, equivalent to the doctorate.

Scandinavian countries were among the early adopters of a modern style doctorate of philosophy, based upon the German model. Denmark and Norway both introduced the Dr. Phil(os). degree in 1824, replacing the Magister's degree as the highest degree, while Uppsala University of Sweden renamed its Magister's degree Filosofie Doktor (Fil.Dr.) in 1863. These degrees, however, became comparable to the German Habilitation rather than the doctorate, as Scandinavian countries did not have a separate Habilitation. The degrees were uncommon and not a prerequisite for employment as a professor; rather, they were seen as distinctions similar to the British (higher) doctorates (D.Litt., D.Sc.). Denmark introduced an American-style PhD in 1989; it formally replaced the Licentiate degree, and is considered a lower degree than the Dr. Phil. degree; officially, the PhD is not considered a doctorate, but unofficially, it is referred to as "the smaller doctorate", as opposed to the Dr. Phil., "the grand doctorate". Currently Denmark and Norway are both awarding the traditional (higher) Dr. Phil(os). degree, and American-style PhDs. Sweden is only awarding the Fil.Dr. degree.

Spain
Doctor Degrees are regulated by Royal Decree (R.D. 778/1998), Real Decreto (in Spanish). They are granted by the University on behalf of the King, and its Diploma has the force of a public document. The Ministry of Science keeps a National Registry of Theses called TESEO.

All doctoral programs are of a research nature. A minimum of 4 years of study are required, divided into 2 stages:


 * 1) A 2-year-long period of studies, which concludes with a public dissertation presented to a panel of 3 Professors. If the projects receives approval from the university, he/she will receive a "Diploma de Estudios Avanzados" (part qualified doctor).
 * 2) A 2-year (or longer) period of research. Extensions may be requested for up to 10 years. The student must write his thesis presenting a new discovery or original contribution to Science. If approved by his "thesis director", the study will be presented to a panel of 5 distinguished scholars. Any Doctor attending the public presentations is allowed to challenge the candidate with questions on his research. If approved, he will receive the doctorate. Four marks can be granted (Unsatisfactory, Pass, "Cum laude", and "Summa cum laude"). Those Doctors granted their degree "Summa Cum Laude" are allowed to apply for an "Extraordinary Award".

A Doctor Degree is required to apply to a teaching position at the University.

The social standing of Doctors in Spain is evidenced by the fact that only PhD holders, Grandees and Dukes can take seat and cover their heads in the presence of the King. All Doctor Degree holders are reciprocally recognized as equivalent in Germany and Spain ("Bonn Agreement of November 14, 1994").

United Kingdom
Further information: Doctorate

Earning a PhD or DPhil infers the title Dr. There is a common misconception (especially among women who are unmarried at the end of their PhD) that this title is specific to the surname which the person had when the degree was obtained. However, this is incorrect and regardless of whether a person changed their name they will not lose the title. Once the title is earned it cannot be removed unless the person requests it to be by Deed Poll.

Designation
The top ten UK universities ranked by research quality according to the Times Literary Supplement with their designatory letters:

Admission
Universities admit applicants to PhD programmes on a case-by-case basis; depending on the university, admission is typically conditional on the prospective student having successfully completed an undergraduate degree with at least upper second-class honours, or a postgraduate master's degree, but requirements can vary.

In the case of the University of Oxford, for example, "The one essential condition of being accepted...is evidence of previous academic excellence, and of future potential." Commonly, students are first accepted on to an MPhil programme and may transfer to PhD regulations upon satisfactory progress and is referred to as APG (Advanced Postgraduate) status. This is typically done after one or two years, and the research work done may count towards the PhD degree. If a student fails to make satisfactory progress, he or she may be offered the opportunity to write up and submit for an MPhil degree.

In addition, PhD students from countries outside the EU/EFTA area are required to comply with the Academic Technology Approval Scheme (ATAS), which involves undergoing a security clearance process with the Foreign Office for certain courses in medicine, mathematics, engineering and material sciences. This requirement was introduced in 2007 due to concerns about terrorism and weapons proliferation.

Funding
In the United Kingdom, funding for PhD students is sometimes provided by government-funded Research Councils or the European Social Fund, usually in the form of a tax-free bursary which consists of tuition fees together with a stipend of around £13,000 per year for three years (higher in London), whether or not the degree continues for longer. Scientific studentships are usually paid at a higher rate, for example, in London, Cancer Research UK, the ICR and the Wellcome Trust stipend rates start at around £19,000 and progress annually to around £23,000 a year; an amount that is tax and national insurance free. Research Council funding is sometimes 'earmarked' for a particular department or research group, who then allocate it to a chosen student, although in doing so they are generally expected to abide by the usual minimum entry requirements (typically a first degree with upper second class honours, although successful completion of a postgraduate master's degree is usually counted as raising the class of the first degree by one division for these purposes). However, the availability of funding in many disciplines (especially humanities, social studies, and pure science subjects) means that in practice only those with the best research proposals, references and backgrounds are likely to be awarded a studentship. The ESRC (Economic and Social Science Research Council) explicitly state that a 2.1 minimum (or 2.2 plus additional masters degree) is required – no additional marks are given for students with a first class honours or a distinction at masters level.

Since 2002, there has been a move by research councils to fund interdisciplinary doctoral training centres such as MOAC which concentrate on communication between traditional disciplines and an emphasis on transferable skills in addition to research training.

Many students who are not in receipt of external funding may choose to undertake the degree part time, thus reducing the tuition fees, as well as creating free time in which to earn money for subsistence.

Students may also take part in tutoring, work as research assistants, or (occasionally) deliver lectures, at a rate of typically £25–30 per hour, either to supplement existing low income or as a sole means of funding.

Completion
There is usually a preliminary assessment to remain in the programme and the thesis is submitted at the end of a 3- to 4-year program. These periods are usually extended pro rata for part-time students. With special dispensation, the final date for the thesis can be extended for up to four additional years, for a total of seven, but this is rare. Since the early 1990s, the UK funding councils have adopted a policy of penalising departments where large proportions of students fail to submit their theses in four years after achieving PhD-student status (or pro rata equivalent) by reducing the number of funded places in subsequent years.

There has recently been an increase in the number of Integrated PhD programs available, such as at the University of Southampton. These courses include a Masters of Research (MRes) in the first year, which consists of a taught component as well as laboratory rotation projects. The PhD must then be completed within the next 3 years. As this includes the MRes all deadlines and timeframes are brought forward to encourage completion of both MRes and PhD within 4 years from commencement. These programs are designed to provide students with a greater range of skills than a standard PhD.

Other doctorates
In the United Kingdom PhD degrees are distinct from other doctorates, most notably the higher doctorates such as D.Litt. (Doctor of Letters) or D.Sc. (Doctor of Science), which may be granted on the recommendation of a committee of examiners on the basis of a substantial portfolio of submitted (and usually published) research. However, most UK universities still maintain the option of submitting a thesis for the award of a higher doctorate.

Recent years have seen the introduction of professional doctorates, which are the same level as PhDs but more specific in their field. These tend not to be solely academic, but combine academic research, a taught component and a professional qualification. These are most notably in the fields of engineering (Eng.D.), education (Ed.D.), occupational psychology (D.Occ Psych.) clinical psychology (D.Clin.Psych.), public administration (D.P.A.), business administration (D.B.A.), and music (D.M.A.). These typically have a more formal taught component consisting of smaller research projects, as well as a 40,000–60,000 word thesis component, which collectively is equivalent to that of a PhD degree.

Overview
In the United States, the Ph.D. degree is the highest academic degree awarded by universities in most fields of study. American students typically undergo a series of three phases in the course of their work toward the Ph.D. degree. The first phase consists of coursework in the student's field of study and requires one to three years to complete. This often is followed by a preliminary, a comprehensive examination, or a series of cumulative examinations where the emphasis is on breadth rather than depth of knowledge. The student is often later required to pass oral and written examinations in the field of specialization within the discipline, and here, depth is emphasized. Some Ph.D. programs require the candidate to successfully complete requirements in pedagogy (taking courses on higher level teaching and teaching undergraduate courses) or applied science (e.g., clinical practice and predoctoral clinical internship in Ph.D. programs in clinical or counseling psychology).

Another two to four years are usually required for the composition of a substantial and original contribution to human knowledge in the form of a written dissertation, which in the social sciences and humanities typically ranges from 50 to 450 pages in length. In many cases, depending on the discipline, a dissertation consists of (i) a comprehensive literature review, (ii) an outline of methodology, and (iii) several chapters of scientific, social, historical, philosophical, or literary analysis. Typically, upon completion, the candidate undergoes an oral examination, sometimes public, by his or her supervisory committee with expertise in the given discipline.

As the Ph.D. degree is often a preliminary step toward a career as a professor, throughout the whole period of study and dissertation research the student, depending on the university and degree, may be required or offered the opportunity to teach undergraduate and occasionally graduate courses in relevant subjects.

Admission
There are 282 universities in the United States that award the PhD degree, and those universities vary widely in their criteria for admission, as well as the rigor of their academic programs. Typically, PhD programs require applicants to have a Bachelor's degree in a relevant field (and, in many cases in the humanities, a master's degree), reasonably high grades, several letters of recommendation, relevant academic coursework, a cogent statement of interest in the field of study, and satisfactory performance on a graduate-level exam specified by the respective program (e.g., GRE, GMAT). Specific admissions criteria differ substantially according to university admissions policies and fields of study; some programs in well-regarded research universities may admit less than five percent of applicants and require an exceptional performance on the GRE along with near-perfect grades, strong support in letters of recommendation, substantial research experience, and academically sophisticated samples of their writing.

Master's degree "en route"
As applicants to many Ph.D. programs are not required to have master's degrees, many programs award a Master of Arts or Master of Science degree "en route", "in passing", or "in course" based on the graduate work done in the course of achieving the Ph.D. Students who receive such master's degrees are usually required to complete a certain amount of coursework and a master's thesis or field examination. Not all Ph.D. programs require additional work to obtain a master's en route to the Ph.D. (e.g., a master's thesis). Depending on the specific program, masters-in-passing degrees can be either mandatory or optional. Not all Ph.D. students choose to complete the additional requirements necessary for the MA or MS if such requirements are not mandated by their programs. Those students will simply obtain the Ph.D. degree at the end of their graduate study.

Time
Depending on the specific field of study, completion of a PhD program usually takes four to eight years of study after the Bachelor's Degree; those students who begin a PhD program with a master's degree may complete their PhD degree a year or two sooner. As PhD programs typically lack the formal structure of undergraduate education, there are significant individual differences in the time taken to complete the degree. Many U.S. universities have set a ten-year limit for students in PhD programs, or refuse to consider graduate credit older than ten years as counting towards a PhD degree. Similarly, students may be required to re-take the comprehensive exam if they do not defend their dissertations within five years after submitting it to their self-chosen dissertation advisors. Overall, 57% of students who begin a PhD program in the US will complete their degree within ten years, approximately 30% will drop out or be dismissed, and the remaining 13% of students will continue on past ten years.

Funding
PhD students are usually discouraged from engaging in external employment during the course of their graduate training. As a result, PhD students at U.S. universities typically receive a tuition waiver and some form of annual stipend. The source and amount of funding varies from field to field and university to university. Many U.S. PhD students work as teaching assistants or research assistants. Graduate schools increasingly encourage their students to seek outside funding; many are supported by fellowships they obtain for themselves or by their advisers' research grants from government agencies such as the National Science Foundation and the National Institutes of Health. Many Ivy League and other well-endowed universities provide funding for the entire duration of the degree program (if it is short) or for most of it.

PhD candidacy
A PhD program candidate, or PhDc (sometimes called Candidate of Philosophy), is a postgraduate student at the doctoral level who has successfully satisfied the requirements for doctoral studies, except for the final thesis or dissertation. As such, a PhDc is sometimes called an "ABD" (All But Dissertation or All But Defended). Although a minor distinction in postgraduate study, achieving PhD Candidacy is not without benefit. For example, PhDc status may coincide with an increase in the student's monthly stipend and may make the student eligible for additional employment opportunities.

Some programs also include a Master of Philosophy degree as part of the PhD program. The MPhil, in those universities that offer it, is usually awarded after the appropriate MA or MS (as above) is awarded, and the degree candidate has completed all further requirements for the PhD degree (which may include additional language requirements, course credits, teaching experiences, and comprehensive exams) aside from the writing and defense of the dissertation itself. This formalizes the "all but dissertation" (ABD) status used informally by some students, and represents that the student has achieved a higher level of scholarship than the MA/MS would indicate – as such, the MPhil is sometimes a helpful credential for those applying for teaching or research posts while completing their dissertation work for the PhD degree itself.

PhDc is not to be confused with Candidate of Sciences, an academic degree that has been used in certain countries in place of PhD.

Vietnam
A PhD title holder must fulfill a number of strict requirements including:
 * - Passing entrance examinations including a professional examination, a foreign language examination, and successfully defending the dissertation proposal
 * - Conducting the research work as approved in the entrance examination
 * - Publishing research results in respective professional journals
 * - Successfully defending the research results twice, first with a scientific panel designated by the university. If passed, the PhD candidate will have to defend in a nation-wide panel including two hidden external reviewers; the panel is formulated by the ministry of education and training.

Vietnam is trying to improve its PhD training quality as well as simplifying the procedures required to obtain the degree.

Models of supervision
At some universities, there may be training for those wishing to supervise PhD studies. There is now a lot of literature published for academics who wish to do this, such as Delamont, Atkinson and Parry (1997). Indeed, Dinham and Scott (2001) have argued that the worldwide growth in research students has been matched by increase in a number of what they term "how-to" texts for both students and supervisors, citing examples such as Pugh and Phillips (1987). These authors report empirical data on the benefits that a PhDc may gain if he or she publishes work, and note that PhD students are more likely to do this with adequate encouragement from their supervisors.

Wisker (2005) has noticed how research into this field has distinguished between two models of supervision: The technical-rationality model of supervision, emphasising technique; The negotiated order model, being less mechanistic and emphasising fluid and dynamic change in the PhD process. These two models were first distinguished by Acker, Hill and Black (1994; cited in Wisker, 2005). Considerable literature exists on the expectations that supervisors may have of their students (Phillips & Pugh, 1987) and the expectations that students may have of their supervisors (Phillips & Pugh, 1987; Wilkinson, 2005) in the course of PhD supervision. Similar expectations are implied by the Quality Assurance Agency's Code for Supervision (Quality Assurance Agency, 1999; cited in Wilkinson, 2005).

International PhD Equivalent Degrees

 * Belgium (Dutch-speaking): Doctor
 * Belgium (French-speaking): Doctorat
 * Brazil: Doutorado
 * Bulgaria: Доктор
 * China: 博士
 * Colombia: Doctorado
 * Croatia: Doktor
 * Czech Republic: CSc. was used till 1998, since 1998 PhD written as Ph.D. is used
 * Ecuador: Doctorado
 * Egypt: Doctorat
 * Estonia: Doktor
 * Finland: Tohtori
 * France: Doctorat
 * Germany: Doktor
 * Greece: Διδακτορικό
 * Hong Kong: 博士Doctor
 * Indonesia: Doktor
 * Iran: دکترا
 * Iraq: دكتوراه (Duktorah)
 * Israel: דוקטורט ("doctorat")
 * Italy: Dottorato di ricerca
 * Japan: 博士
 * Korea: 박사
 * Latin America: Doctorado/Doctorate
 * Latvia: Zinātņu doktors
 * Lithuania: Daktaras
 * Macau: 博士Doutoramento
 * Malaysia: Doktor Falsafah
 * Mexico: Doctorado
 * Mongolia: Эрдэмтэн
 * Netherlands: Doctor
 * Norway: no: Doktorgrad
 * Peru: Doctorado
 * Philippines: Doktor
 * Poland: Doktor
 * Portugal: Doutoramento
 * Romania: Doctorat
 * Russia: Кандидат наук (Candidate of Sciences)
 * Singapore: Doctor
 * Serbia: Доктор
 * Spain: Doctorado
 * Syria: دكتوراه (doktorah)
 * Taiwan： 博士
 * Thailand: ดุษฎีบัณฑิต
 * Turkey: Doktor
 * Ukraine: Кандидат наук
 * Vietnam: Tiến sĩ