There must always be data that should be collected, organized, analyzed, and interpreted in any research undertaking. No research activity can be succeeded without necessary data so the data collection is important phase of the research process.
According to Frederick Lamson Whitney, data are the things we think with. They are the raw materials of reflection, until by comparison, combination, and evaluation they are stepped up to higher levels of generalization, where again they serve as basic materials for higher and higher thinking.
Data can be classified in different ways. It may be objective or subjective. They may be quantitative or qualitative They may be attributes or variables.. Data may also be classified according to the methods or types of research that the researcher may use. It can also classify as primary or secondary or as raw or derived.
There are methods or techniques used to collection data namely: the questionnaire, observation, the interview, psychological tests and library technique. The researcher must choose the most appropriate method or technique that is suitable and most useful to his/her research projects.