Our interview process currently consists of several coding questions, technical questions and experiences at their current and previous jobs. Coding questions are typically a single method that does something (Think of it as fizzbuzz or reverse a string kind of question)

We are planning on introducing an additional step where we give them a business problem and ask them to draw a flowchart, activity, class or a sequence diagram.

We feel that our current interview process does not let us evaluate the candidate's thinking at a higher level (which is relevant for architect/senior level positions).

To give you some context, we are a mid size software company with around 30 developers in the team.

If you have this step in your interview process, how has it improved your interviewing veracity? If not, what else has helped you evaluate the candidates better from a technical perspective.