Dr. Peiffer recently conducted a study on marital satisfaction. After surveying 100 married couples, she found that couples who commit to a date night once a week report higher marital satisfaction than those who do not date weekly. To further investigate her findings, she asked 50 unhappy couples to date once a week. After 12 weeks, she found that all of the couples reported an increase in marital satisfaction. She wanted to know more about the specific impact of the date night on couples. She decided to follow Mr. and Mrs. Malone for five years. During this time, she surveyed only this couple regularly and measured any changes in the relationship. What type of study does this describe?
