Each year, the graduating class at Stoner High is given a survey to assess its drug use. The same survey has been used for 10 years, allowing school administrators to track changes in drug use over time. This method of survey collection is referred to as

A trend study

Explanation:

A trend represents a pattern in which things develop, the trend is characterized by time changes. A trend study is a method of gathering data of people from a particular population over time. The trend study generally observes a behavior as it develops over time among the study participants.

Example

For every in our illustration the graduating students each year are given the same assessment test to check drug use. This test has been administered for ten years and this change in time has created a pattern over the years. These patterns or trends make it easy to track changes.

The drug use assessment by the student over time shows the trend in drug use among the students for ten years. This scenario is that of Trend study