Doctor of Science (Latin: Scientiae Doctor), usually abbreviated Sc.D., D.Sc., S.D., or D.S., is an academic research degree awarded in a number of countries throughout the world. In some countries, "Doctor of Science" is the degree used for the standard doctorate in the sciences; elsewhere the Sc.D. is a "higher doctorate" awarded in recognition of a substantial and sustained contribution to scientific knowledge beyond that required for a Doctor of Philosophy (PhD). It may also be awarded as an honorary degree.
In Algeria, Morocco, Libya and Tunisia, all universities accredited by the state award a "Doctorate" in all fields of science and humanities, equivalent to a PhD in the United Kingdom or United States.
Some universities in these four Arab countries award a "Doctorate of the State" in some fields of study and science. A "Doctorate of the State" is slightly higher in esteem than a regular doctorate, and is awarded after performing additional in-depth post-doctorate research or achievement.
Similar to the situation in the US, Japanese universities offer both the Ph.D. and the Sc.D. as initial doctorates in science.
In India only a few prestigious universities offer Sc.D./D.Sc.in science which is obtained in Graduate School after satisfactory evaluation of knowledge, research accomplishment, and a doctoral defence. The oldest institute to award a D.Sc. degree in India is Rajabazar Science College, University of Calcutta.
Higher education institutes in Thailand generally grant Ph.D. for research doctoral degree, except some universities such as Chulalongkorn University award D.Sc. In exception, Mahidol University can grant both Ph.D. and D.Sc. Doctoral students in Faculty of Science are always awarded Ph.D., but some other programs award D.Sc.
The higher education institutes in Uzbekistan also grant D.Sc. degrees. As an example, the National University of Uzbekistan and the Uzbekistan Academy of Sciences offer D.Sc. in various fields.
In these countries there are some related doctoral degrees with very similar names, these are the:
All these doctoral degrees are equivalent to the Ph.D. or Sc.D. of the American system. Until German Reunification, universities in East Germany also awarded the Dr.Sc. However, the East German Dr.Sc. was not equivalent to the Ph.D. since it was adopted to replace the German Habilitation and therefore was equivalent to this higher-level qualification. After reunification the Habilitation was reintroduced at universities in Eastern Germany.
The procedure of habilitation is normally required to receive officially the "venia docendi", which entitles the candidate to lecture at universities (Privatdozent, for men, or Privatdozentin, for women). The academic degree after the successful habilitation is e.g. Dr. rer.nat. habil., by adding the suffix "habil." to the earlier received Doctors degree.
In Switzerland, the Dr sc. is a doctoral degree awarded only by the two Swiss Federal Institutes of Technology (EPFL and ETHZ), the University of Fribourg and the Department of Informatics of the University of Zurich. The Swiss Dr sc., like the D.Sc. in the US, is equivalent to the PhD. It is earned with the approval of a committee on the basis of original research, publications, and extensive applied professional contributions and is awarded in doctoral level science and technology programs. Since 2004 the Dr sc. is the only doctoral degree awarded by the ETH Zurich. The École polytechnique fédérale de Lausanne awards the degree Docteur ès sciences, abbreviated Dr ès sc.and translated into English as PhD.
In Poland "Doctor of Sciences" or "Habilitation" (doktor habilitowany or dr hab. in Polish) is the degree higher than Ph.D. and it is awarded for substantial accomplishments in teaching, research and service after getting the Ph.D. degree (usually up to 8 years after Ph.D.). It is very similar to the equivalent habilitation degree in Germany and Austria. It is also very similar (in terms of requirements) to Associate Professor with tenure.
The highest scientific degree in Poland is "professorship" or "full professor" (tytu? naukowy profesora, profesor tytularny), which is called a scientific title of professor. "Habilitation" has been a mandatory requirement for many years to apply for full professorship in Poland.
In Ireland, the United Kingdom and the countries of the Commonwealth, such as India (in the Indian Institute of Technology, Bombay), the degree of Doctor of Science (DSc or ScD) is one of the Higher Doctorates. In some older universities it typically has precedence after Divinity, Laws or Civil Law, Medicine, and Letters, and above Music. The degree is conferred on a member of the university who has a proven record of internationally recognised scholarship. A candidate for the degree will usually be required to submit a selection of their publications to the board of the appropriate faculty, which will decide if the candidate merits this accolade. The award or obtaining of a regular PhD degree is not in any way a pre-requisite for obtaining a DSc, as, for example, it can happen in the sciences that an academic who does a lot of publishing can be awarded a DSc without ever having done a PhD degree.
In former times the doctorate in science was regarded as a greater distinction than a professorial chair and hence a professor who was also a D.Sc. would be known as Doctor. The Doctor of Science may also be awarded as an honorary degree, that is, given to individuals who have made extensive contributions to a particular field and not for specific academic accomplishments. It is usual to signify this by adding D.Sc. h.c. (for honoris causa).
In the Czech Republic and Slovakia "Doctor of Sciences" (DrSc. behind the name), established in 1953, is equivalent to the degree of Doctor of Science in the sense in which the D.Sc. is used in the Commonwealth. It is the highest academic qualification, different from both Ph.D. and PhDr. titles. In the Czech Republic, DrSc. has not been awarded since 2001; instead, since 2006, a "Doctor of Sciences" degree (DSc. behind the name) has been awarded, not by universities but by the Czech Academy of Sciences mostly for research in the field of natural or formal science. In Slovakia, "Doctor of Sciences" (Dr.Sc.) is awarded by the Slovak Academy of Sciences.
In Hungary, "Doctor of Sciences" (D.Sc.) is awarded by the Hungarian Academy of Sciences.
In Finland, most doctoral degrees awarded in the fields of natural sciences, technology and economics are termed D.Sc. degrees in English, with a suffix indicating the field of study. However, there is no translation of the term Doctor of Science to Finnish. For example, the proper translation for the doctorate in technology (tekniikan tohtori) would be D.Sc. (Tech.), whereas a doctorate in economics and business administration (kauppatieteiden tohtori) would be translated as D.Sc. (Econ.). When conversing or writing in English, the prefix Dr may be used to address a holder of a doctoral degree awarded in Finland. The degrees are equivalent to filosofian tohtori (FT, English: PhD), but FT is usually awarded only in general sciences, not in specializations like engineering, economics or medicine.
In France, the Doctor of Sciences degree (doctorat ès sciences also called doctorat d'État) was a higher doctorate in the fields of experimental and natural sciences, superseded in 1984 by the habilitation.
In Denmark, Dr Scient. is a higher doctorate.
In Bulgaria, PhD is the highest education level and first science degree. Doctor of Science is the second and the highest science degree.
In the former Yugoslavia, (Croatia, Serbia, Bosnia and Herzegovina, Montenegro, Slovenia, North Macedonia), title doktor nauka or doktor znanosti (literally "doctor of science") is used in a much broader sense than D.Sc., simply referring to a field of academic study - from art history (doktor znanosti/nauka povijesti umjetnosti), philosophy (doktor znanosti/nauka filozofije), and literary studies (doktor znanosti/nauka knji?evnosti) to hard sciences such as molecular biology (doktor znanosti/nauka molekularne biologije). It is therefore formally recognized as a Ph.D. degree.
Starting in 2016, in Ukraine Doctor of Philosophy (PhD, Ukrainian: ) is the highest education level and first science degree. "Doctor of Sciences" (DSc. Ukrainian: ?) is the second and the highest science degree, awarded in recognition of a substantial contribution to scientific knowledge, origination of new directions and visions in science. A PhD degree is a prerequisite for heading a university department in Ukraine.
In Belarus "Doctor of Sciences" (D.Sc., Belarusian: ) is the highest level of education that follows a PhD. Is awarded by The Higher Attestation Commission under the aegis of the President of the Republic of Belarus.
In the United States, the formally recognized traditional Doctor of Science is an academic research doctoral degree awarded by research universities. The academic research Sc.D. (or D.Sc.) is considered by both the United States Department of Education and the National Science Foundation to be equivalent to the more commonly awarded Ph.D.
The first North American Sc.D. was inaugurated by Harvard University in 1872, when graduate studies first began at Harvard, and where the Ph.D. and Sc.D. degrees were introduced in the same year. The Doctor of Science research degree is earned with the formal dissertation defense and approval of a committee on the basis of original research and publications, and it is awarded predominantly in doctoral-level science programs, such as engineering, medical and health sciences, and health economics.
Although rarer than the Doctor of Philosophy, the Doctor of Science research degree has been awarded, and continue to be offered, by institutions such as Columbia University, Bowie State University, The George Washington University (although as of 2011 the University decided to offer only the more widely recognized Ph.D. degree), Harvard University, Middle Georgia State University, Johns Hopkins University, Massachusetts Institute of Technology, Robert Morris University, Towson University, Tulane University., University of Baltimore, and Marymount University.
A few university doctoral research programs offer both the Sc.D. and Ph.D. degrees in the same academic field, such as Johns Hopkins University and Massachusetts Institute of Technology, with identical requirements for obtaining either. Currently, research programs that offer the formal research Sc.D. but not the Ph.D. degree for a given field include several doctoral programs at Harvard University, Boston University, Capitol Technology University, Texas Tech University Health Sciences Center and Dakota State University. The University of Baltimore, School of Information Arts and Technologies offers an Sc.D. degree in Information and Interaction Design, a program focused on usable design/user experience (UX) and Human Computer Interaction (HCI).
There are programs where the Sc.D. and Ph.D. have different degree requirements, though the two degrees are officially considered equivalent. The Engineering school at Washington University in St. Louis, for example, requires four more graduate courses, which can be completed in one year in conjunction with research duties, in the D.Sc. program than the Ph.D. degree, while the Ph.D requires teaching assistance services. The Johns Hopkins University also offers both Ph.D. and Sc.D. in certain programs, with only minor differences in university administration of the degrees. In some institutions, the Sc.D. has been converted to the Ph.D. For instance, the doctoral degree in biostatistics at Harvard recently converted from Sc.D. to Ph.D., even though the doctoral degree structure and requirements have remained identical.
In addition, some institutions offer Doctor of Science degrees through distance learning. They include Rocky Mountain University of Health Professions in health science, Westbrook University in health sciences, holistic health science, holistic nursing and clinical nutrition,  Aspen University in computer science, Jacksonville State University in emergency management and Spertus Institute for Jewish Learning and Leadership in Jewish studies.
In Mexico the PhD level is considered a doctoral degree (level 8) similar to the doctorate degrees in Canada and the United States. The Doctor of Sciences degree is instead recognized as a Higher Degree (Grado Proprio).
In Russia and various other post-Soviet states, as well as in some of the former Communist Bloc countries, the status of Russian Doktor nauk (literally 'Doctor of Sciences') is a post-doctoral degree. The degree has no American equivalent but rather is similar to German Habilitation.
In Argentina the formal title Doctor of Science would be attributed to different fields of the hard or soft sciences. To get into an Argentine Ph.D. program the applicant must have experience in research and at least an Engineering, Licentiate or master's degree:
In Brazil only the Doctor in Sciences (D.Sc.) category is recognized as a higher doctorate, generally followed by the concentration area (program field).
This kind of doctorate is obtained in Graduate School after satisfactory evaluation of knowledge, research accomplishment, and thesis defense. This doctorate is comparable to a Ph.D. program found in other countries. In the state of São Paulo, the doctorate title is the second highest academic title given by the state's universities (University of São Paulo (USP), State University of Campinas (UNICAMP) and São Paulo State University (UNESP)) and most Federal Universities, such as the Federal University of São Paulo (UNIFESP). The highest academic title is the Livre-Docência, which is not equivalent to the German Habilitation, since "Livre-Docência" is not a requisite to be a professor in Brazilian universities, and German Habilitation is a requisite to be a professor in German universities.