"Scope creep can be a real problem that results in unhappy customers/stakeholders and a blown budget and/or timeline. In my experience, it tends to occur when there is a lot of client and/or stakeholder feedback that the project manager doesn't correctly manage. Feedback is good, but many times it comes along with additional requests.

I've learned that the best way to handle these kinds of requests is to clearly explain to the customer or stakeholder how fulfilling a specific request will change the cost and timeline of the project. Then, I only add this to the project scope if the client/stakeholder accepts these cost and timeline changes. I also make sure that the scope of the project is definitively spelled out at the beginning of the project and that I keep track of the smaller tasks and goals as they are achieved so we don't veer off-course. In the instances when scope creep does occur, I move quickly to establish and communicate new expectations."

Discuss the various methods you use to prevent scope creep during project planning, execution, and any applicable support periods that occur after project implementation. Also, briefly discuss your method for looking for ways to address new requests that are 'showstoppers' or directly tied to the success of your project. This will help convince your interviewer that you are agile and can adjust the project plan to accommodate critical items necessary for a positive outcome.