What term refers to a construct that serves as a measuring rod against which specific cases can be evaluated?

The correct choice is "ideal type." In sociology, the concept of an ideal type is used to create a model or standard against which real-world cases can be compared. Developed by sociologist Max Weber, an ideal type is a theoretical construct that encapsulates the fundamental characteristics of a particular social phenomenon, allowing researchers to assess and analyze actual situations in relation to this model.

In using an ideal type, sociologists can better grasp complexities in social realities by simplifying them into essential traits, facilitating comparisons and evaluations. This is particularly useful in understanding diverse social structures, practices, or behaviors, as it generates a clearer framework for sociological analysis.

The other options do not adequately serve this specific purpose: a prototype typically refers to an original model or first design, a framework provides a structure for understanding but is more generic, and a benchmark usually relates to a standard of measurement in various fields, not specifically tailored for sociological evaluation.