A non-government organization conducted a study in a Gram Panchayat to see the impact of a campaign approach on the enrolment and retention of rural elementary school children. This is an example of

An NGO manipulating a campaign approach in a real Gram Panchayat is a field experiment.

A descriptive study would only portray conditions without manipulating a factor.

Ex post facto research examines effects after the cause has already occurred.

Historical research reconstructs past events from records.

The intervention here is applied deliberately in a natural setting.

The measured outcomes are enrolment and retention of children.