Provides evidence showing that although analytic hierarchy process (AHP) is effective to use for management decision making, it can be defective if used improperly. AHP becomes one of the essential multi‐criteria, decision‐making methods used by both management practitioners and academics. With the development of computer software packages, its usage expands vastly across different business and management areas. An example is presented to illustrate how the defective methodology of AHP can contaminate the findings and subsequent analyses and discussions. The “defected” papers disclosed a defective methodology that generated invalid findings. This paper first points out what the query is. Then, possible reasons behind the invalid findings are described, which are also explained with mathematical expressions. Apparently, “defected” papers may infect those who use them and transfer the risks out into the academic world. Asserts its researchers’ responsibility to raise any risky papers for discussions once they have found them, and advises the authors of these papers to take a positive attitude in dealing with queries and critiques.