Later, in a combined way techniques are used such as brainstorming (BM), importance technique with Likert scale, and GRA method. The purpose is to determine the main causes, i.e., having the maximum weight, the most impact on incompatibility. The GRA method has application for a small number of **data** (that is, even 4 data), where it is a common phenomenon during the analysis of causes of incompatibility [38,39].