Mutation testing is considered as one of the most effective quality improvement technique by assessing the strength of the actual test suite. If no test is able to kill a given mutant, this means that the tests are not strong enough and we need to write additional one that will be able to kill this mutant. However, mutation testing is very time consuming. In this paper we investigate if it is possible to reduce the scope of the mutation analysis by running it only on the new or changed part of the code. Using data from the real open-source projects we analyze if there is a relation between mutation scope reduction and effectiveness of the mutation analysis.