From the Leedy textbook : "The research problem or question is the axis around which the whole research effort revolves. The statement of the problem must first be expressed with the utmost precision; it should then be divided into more manageable subproblems. Such an approach clarifies the goals and directions of the entire research effort." The usual strategy is to find a general area of research, then a more specific area, and finally a research problem in the specific area. For example, one might be interested in the general area of handwriting, more specifically of handwriting forgery, and arrive at the problem of detecting forgeries by estimating the wrinkliness of the handwriting.
In traditional doctorate programs the area of research and even the precise research problem are sometimes formulated by a student's advisor. In the DPS program, however, the area of research and especially the precise problem to be examined are usually formulated by the student. The problem must be clearly defined, worthy of attention (solid response to the "so what?" question), well motivated, and break new ground (unique). The scope must be narrowed to manageable size within the allotted timeframe, and the researcher must especially resist the temptation to undertake a problem that could take a lifetime.
The research problem comes about from knowledge and understanding of a topic or area of work. Because all DPS students are required to have at least five years of computing work experience, they come into the program with considerable computing knowledge. With this background problems often arise by reading the literature on a chosen topic, and new researchers in particular often link their work closely to existing literature. When reading research papers, keep in mind the following points:
The process of arriving at the final problem is highly nonlinear, and typically involves a repeated cycle of writing and returning to further analysis and reading. Writing can itself be a process of discovery that reveals gaps in the argument and suggests new avenues of research.
The fundamental ingredients of research are curiosity, energy to pursue various avenues, imagination, flexibility to overcome inevitable problems, and good judgment in all areas of the work. Research involves intense concentration over long periods, allocating regular time commitments to keep the effort moving forward. The effort is usually so intense that it is hard to stop thinking about the research, and the researcher often wakes up in the morning with potential solutions or new ideas.
 Leedy and Ormrod, Practical Research, 8th Edition, Prentice, 2005.