The key to this question is how quick and confident you can answer the question. Even though you have a good answer but if you react slowly and indecisively to this question, the interviewers would be doubtful about your practical experience in managing people.

Taking care of the people and to make sure they perform is surely what your boss mostly concern about your leadership. All you have is a good communication to your subordinates that reinforce your requirement and the constant checking of their performance against your benchmark.

So a 4-step process should take place

Good goal setting with your sub-ordinates under formal and informal meeting. Appraisal is surely the most formal way to mutually agree the expectations from you as well as his/her agreement to the expectation. To make sure your staff performs as you expect requires your sub-ordinate understand what he/she has to achieve at the first place.

The second step is to create a set of measurement or performance indicators to track the performance of your staff.

Regular review of those indicators and discuss and investigate if any one is out of control or not meeting the expectations. This serves as the feedback mechanism. Hence you and your staff would be involved in the course of the performance checking

Award and Penalty system is put in place for the staff who makes up their effort to achieve what ought to achieve. And for those who could not, it is the time to evaluate if the objective is realistic for him/her and your role should be judging if an extended period should be granted for the performance tracking or other measures should be taken place like transferring to other job assignment if you find your staff have done their best or the worst case leaving the present job position.