Postgraduate research represents a formal area of study that is recognized by a university or institute of higher learning. The notion of "postgraduate" refers to studies following a undergraduate degree. Postgraduate research either occurs within a postgraduate degree that also includes taught elements, such as the thesis completed after the all but dissertation stage of an American-style Doctor of Philosophy (PhD) degree, or refers to research degrees common in Commonwealth countries such as a masters by research or British-style doctorate. Structure The structure of postgraduate research programs can vary significantly from one country to another. To enter into a PhD program in the United States, students generally must have some form of prerequisite study beyond their basic graduate qualification. This may be a Master's coursework program, which acts as a qualifier for entry. In other countries, entry to Doctoral or Master's research programs is based on the academic track record of the candidates in their undergraduate degrees. Many students confuse the notion of postgraduate research with “invention” and “discovery”. Postgraduate research ultimately represents an apprenticeship in the field of research. In his textbook, Key Factors in Postgraduate Research – A Guide for Students. Dario Toncich explains that the objective of postgraduate research is not necessarily to make a breakthrough invention or, indeed, a major scientific discovery. It is, rather, a mechanism by which graduate students learn how to undertake a systematic investigation, founded upon the work built by peers in the field, and then to extend the current state of knowledge. In the context of assessing a postgraduate research program, it is generally the systematic process of research and investigation that is given more attention than the level to which knowledge is extended. The title "doctor" emanates from the Latin word docera—to teach. Hence there is an expectation that the recipient of a doctorate would go on to become some form of "teacher" in the broad sense of the word. History In the 19th century, postgraduate research was a rarity, with countries such as the United States only having a small number of candidates across their university spectrum. However, by the start of the 21st century, postgraduate research, and postgraduate qualifications, had become commonplace. In any one year, at a global level, there are hundreds of thousands of candidates undertaking postgraduate research programs. For this reason the nature of postgraduate research has also changed. At Doctoral level, there is some