Hardly anything is more frustrating in IVR usage than encountering a design in which callers can enter a loop – making a series of choices in which they unintentionally wind up back at a dialog step they've already gone through.

One way to detect loops is to step through the detailed design while creating detailed use cases (also known as scenarios-of-use), as opposed to reviewing a large design page by page. If fortunate enough to have a tool that automatically generates test cases, designers should also perform a review of the test cases to uncover any undesirable experiences such as looping.

Another best practice to follow is to keep counters of how many times a caller is prompted for certain things (like an account number) and put a cap on the tries. Once the maximum number is hit, either provide an alternate method for information-gathering, disconnect the call, or allow an agent transfer. If a caller wasn't able to provide a valid account number the first 3 times the IVR asks, chances are by the 10th time, she still won't be able to.