HOW TO ANALYZE DATA THROUGH MODELING

—ON THE PRINCIPLE OF DATA SIMPLIFICATION—

Abstract

Skilful and non-fictious model-building requires simultaneously two contradictory conditions. By the first, the model should be made to fit the actual phenomena, and by the second, it should be handled with ease. The essential part of data-analysis usually amounts to an input-output relation, where the input is the so-called data and the output is decision. In other words, data-analysis is the process of simplifying data for the convenience of decision. Some principles of simplification are presented. Especially in the case of model-fitting, the necessity for giving some subjective judgements is emphasized. As an example of the common principle of simplifing data, concepts of the simplest sufficient information and of the most efficient information are proposed. To increase fittness of model the necessity for modification of preassigned model is also emphasized. From the actual point of view, more global process of simplification must be considered, In this process, the input consists of the various types of information and the output is just the final conclusion. There may be no general principle of describing such global inputoutput relation. The true and reasonable data-analysis, however, must be grasped as a part of this global input-output relationship.