Deduction vs. Induction

Deductive research is the process of taking general statements and making them more specific. The researcher must rely on a general statement or theory to deduct any further information (Shank, 2008). In deductive research, the researcher trusts that the general statement or theory is reasonably accurate. I may do research based on the idea or theory that humans experience support through fellowship with others, and determine that cancer support groups are supportive for cancer patients.

Inductive research is somewhat the reverse of deductive research in that it takes a specific observation and moves toward a more abstract generalizations (Blaikie, 2008). For example, I may look at support groups for cancer patients to determine why they are supportive.

I believe it helps to look at the root words. Deduce means to come to a conclusion based on known information, whereas induce means to establish or bring something about based on observations (Blaikie, 2004; Shank, 2008). To apply these words to research, deductive research comes to a conclusion based on known information or a theory, whereas inductive research induces a new idea based on observations.

The ocean is at the end of my street. Using deduction, if I do not stop at the end of my street, I will drive into the ocean. Alternatively, after watching several cars drive into the ocean, I learn through inductive research or observation, that when cars drive into the ocean, they fill up with water.

The basic difference between deduction and induction is how and where theory is used in the equation. In deductive reasoning, we start (at the top) with the theory, from which we determine a hypothesis, then make observations (Shank, 2008). We would end with a confirmation of the original theory or additional information that contests or disproves the theory.

Inductive reasoning begins from the bottom with an observation, from which we observe patterns and generalities (Fox, 2008). Then we generate a hypothesis and finish with a theory. The theory is central in both, and the concepts of top-down and bottom-up are based on where the theory functions in the process (Trochim, 2000).

Further, I think of inductive as open-minded and deductive as narrow-minded. Like many diffuse processes in life, it is improbable to think that research should be one or the other. As we have learned, most research processes include both types of reasoning (Creswell, 2008).

Blaikie, N. (2004). Induction. In M. Lewis-Beck, A. Bryman, & T. Liao (Eds.), Encyclopedia of social science research methods. (pp. 487-488). Thousand Oaks, CA: SAGE Publications, Inc. doi: 10.4135/9781412950589.n422

Fox, N. (2008). Induction. In Lisa M. Given (Ed.), The SAGE Encyclopedia of Qualitative Research Methods. (pp. 430-431). Thousand Oaks, CA: SAGE Publications, Inc. doi: 10.4135/9781412963909.n212

Shank, G. (2008). Deduction. In Lisa M. Given (Ed.), The SAGE Encyclopedia of Qualitative Research Methods. (pp. 208-209). Thousand Oaks, CA: SAGE Publications, Inc. doi: 10.4135/9781412963909.n105

Trochim, W. (2000). The Research Methods Knowledge Base, 2nd Edition. Atomic Dog Publishing, Cincinnati, OH.