CONFIDENCE FP7 project is developing a care system for the elderly based on measurements of locations of radio tags attached to a human body. Posture classification is the basis of reasoning in CONFIDENCE. We first applied a data mining approach to recordings of human behavior in order to develop classifier of posture. However, evaluations with separate training and test set scenario show over fitting. Therefore, we considered enriching classifier by human modification. Posture classifier was developed by human modification of induced decision trees. Besides the 5% improvement in accuracy compared to support vector machines and a significant 11% compared to decision trees, we also expect better robustness of this classifier in real-life tests.