Extreme Case

An extreme case is a case that has a value on a variable that is at the limit of the possible values. For example, in the study of age in a community, the most extreme high value may be 95 years, and the most extreme low value may be 18 years. These represent extreme cases, but they may or may not be outliers. An outlier necessarily falls far from the other values, but an extreme case may not do this. For example, in an age study, there may be many respondents in their 80s and 90s, which would mean that an age of 95, though extreme, does not really lie out from neighboring values. In contrast, if below 95, the next highest age was 72, then clearly 95 would be an outlier, as well as being an extreme case.