This dissertation aims to show the influence of factors on our perception and consequent evaluation of data, respectively our assessment of situations. Furthermore, it deals with the question to what extent rationally abstracted processes are common in the medical-pharmaceutical field. Overall, this dissertation indicates that limited evidence of abstracted approaches in the medical-pharmaceutical context can be found. Furthermore it is shown that drug evaluations, in particular the risk evaluation( even in itself) , are subject to strong subjective factors that distort the results.