Limited Complexity of Questions
It is difficult to get people to elaborate on their responses by phone. The reason is that most phone interviews must be limited to five or 10 minutes. People would hang up with longer telephone surveys, resulting in partially completed interviews. Therefore, companies using phone interviews generally keep their questions and answers relatively brief. Many of these questions must be multiple-choice in nature instead of open-ended. The open-ended questions are more informative because they allow customers to elaborate why they responded as they did on multiple-choice questions.