Decision making is mostly based on decision concepts and decision models built in decision support systems. Type of decision problem determines application. This paper presents a conceptual decision model that utilises rule- based methodologies, numerical algorithms and procedures, statistical methodologies including distributions, and visual support. Selection of used decision concepts is based on case-based needs. Fine tuning of the model is done during construction of the computer application and analysis of the case examples. A kind of decision table is built including pre-filtered decision options and carefully chosen decision attributes. Each attribute is weighted, decision table values are given, and finally total score is calculated. This is done with a many-step procedure including various elements. The computer application is built on G2 platform. The case example choice of career is analysed in detail. The developed prototype should be considered mostly as an advisory tool in decision making. More important than the numerical result of the analysis is to learn about the decision problem. Evaluation expertise is needed in the development process. The model constructed is a kind of completed multi-criteria decision analysis concept. This paper is also an example of using a theoretical methodology in solving a practical problem.