noun
observational study
A research method in which subjects are observed without intervention, commonly used in epidemiology and social sciences.
この観察研究では、参加者の生活習慣を長期間追跡した。
In this observational study, the participants' lifestyle habits were tracked over a long period.
実験研究 involves active intervention by the researcher, while 観察研究 only observes without manipulation.
Compound of 観察 (observation) and 研究 (research).