In this interrupted case study students analyze the complexities surrounding identification and confirmation of cancer clusters. The case challenges students to consider the evidence from two different perspectives; a local family physician representing the community, and a cluster investigation officer who has worked on several cancer cluster investigations. This case was inspired by the discussion about a possible cancer cluster in Clyde, Ohio, where around 20 cases of childhood cancer since 2001 fueled public concern, leading to an investigation by the Ohio department of health in 2006. This case was designed for introductory courses in biology and environmental sciences, taken by both science majors and non-science majors. In addition to introductory college classes, this case could also be used in advanced high school biology classes.