Indirect Approach

roundabout method, circuitous way

The Indirect approach was a strategy developed by Basil Liddell Hart after World War I. His strategy called for armies to advance along the line of least expectation against the least resistance. His theory was the opposite of the tactics used during World War I. While he originally developed the theory for infantry, contact with J. F. C. Fuller helped change his theory more towards tanks. The indirect approach would become a major factor in the development of blitzkrieg.
See more at Wikipedia.org...

is one where the true purpose of a research project is disguised. Indirect approaches are used when revealing the true purpose of the research would bias the responses given by participants.