What is a decision making method in which a panel of exports responds to questions and to each other until an agreement is reached on how a specific issue should be handled?

The decision-making method you are referring to is known as the Delphi technique. In this approach, a panel of experts answers questionnaires in multiple rounds, with feedback provided after each round. This iterative process allows the experts to refine their opinions and reach a consensus on how to handle a specific issue. The Delphi technique is often used in forecasting and strategic planning.