ride herd on someone/something

ride herd on (someone or something)

To closely observe or monitor someone or something to supervise or maintain control. An allusion to a cowboy riding on his horse to keep a herd of cattle in order. We want the groups of students to work independently, but we should have a teacher riding herd on each one to make sure they stay focused. Being a camp counselor is a lot of fun, but having to ride herd on a bunch of kids for two weeks at a time can be exhausting.
See also: herd, on, ride

ride herd on someone/something

AMERICAN
If someone rides herd on other people or their actions, they control them. It's his job to ride herd on organizers to keep them on schedule. Note: People sometimes use over instead of on. The ideal situation is one where everyone feels responsible and no one person has to ride herd over the others. Note: Originally, `riding herd' involved patrolling on horseback around a herd of animals, in order to make sure none of them wandered away.
See also: herd, on, ride, someone, something