PhD is essentially a scientific research that aims to add new knowledge to the existing one. This means that the doctoral candidate in his doctoral thesis should fill a gap in existing research and build on his research. PhDs are refraining from traditional student assignments, as Doctoral theses are not required to show whether the candidate doctor knows the subject, which is assumed to be a given but is required to create new knowledge.
This of course means that a PhD thesis can use a variety of research, such as qualitative research and triangulation. The goal is not to confirm existing knowledge, but to create new ones.
The doctoral dissertation lasts for 4 to 6 years and is a painstaking effort, especially if the doctoral candidate has other duties, such as work and family, which means that he has to balance the time he spends on the Ph.D. Thesis and the other obligations . Finally, it is important to know that the student is asked to defend his research and the originality of his proposal in the final presentation that will be made before other academics.