Simple and convenient method of determining the hierarchy model

The first step of applying analytic hierarchy process (AHP) to make a decision is to determine the hierarchy model. For this, the mathematical method introduced by the present references is based on reachability matrix, which is usually accomplished with a computer. In this paper, the characteristics of hierarchy model of AHP are sufficiently considered, which are strict relativity between two close together layers and non-relativity with each other between two elements. A simple and convenient method is presented and illustrated, named as delete-row method (DRM). The correctness of the method is strictly proved. It is using the method to determine the hierarchy model that needn't calculate reachability matrix and so on. It can be completed only by artificial calculation.