Application characteristics of the law of system completeness

Some aspects of the Law of system completeness appearance in technical, information and economic systems are considered in the report. The main system elements revelation technique including a set of criteria for checking of model adequacy to a real system is being proposed. Special attention is being paid to control parameters and control element revelation and its relation with background. A lot of examples are analyzed. It is considered a way of mistake avoiding while main system elements revealing and mistakes of the following analysis.