Generally speaking, in second language research it is useful to distinguish between BASIC (or theoretical ), APPLIED, and PRACTICAL research.

BASIC RESEARCH is concerned with knowledge for the sake of theory. Its design is not controlled by the practical usefulness of the findings.

APPLIED RESEARCH is concerned with showing how the findings can be applied or summarized into some type of teaching methodology.

PRACTICAL RESEARCH goes one step further and applies the findings of research to a specific "practical" teaching situation.

A useful way to look at the relationships among these three research types is illustrated in the diagram below. Each of the three different types of research contributes to the other in helping revise and frame the research from each category.

For example, practical research may be based on theory that came from previously done basic research. Or, theory may be generated by the combination of results from various practical research projects. The same bidirectional relationship exists between applied research and basic research or practical research.