The journal impact factor (JIF) and the Hirsch index, are two widely used parameters for evaluating scientific achievement. The JIF is a parameter which shows the citation score of a journal over the previous two years. The Hirsch index is a simple index to measure the citation performance of individual scientists. These achievement indicators can be used to evaluate research and are thus an indicator for scientific output. Nevertheless, they should not be used as a measurement of scientific quality. Scientific quality not only depends on citation scores, but also on originality, societal and scientific impact, robust methodology and validity and should therefore be evaluated on these parameters. Little is known about the influence that these factors have on science in general and on scientists but there is some evidence suggesting detrimental effects on scientific practice and quality.