Test participants in silence. Provide the individuals you are testing with a reading comprehension assessment without any music playing. These tests vary considerably depending on the age and skill level of the reader, so choose a test that works for the group you are working with. Many free assessments are available on the Internet or can be purchased.
Wait a few days and re-administer the test with music playing. Choose music depending on what you wish to test. Classical music will likely be more calming than heavy metal music, for example. However, if you wish to learn about the effects of heavy metal music, choose that genre.
Control the study conditions. Make sure that the environment in which you re-administer the test is the same except for the music.
Score the tests. Compare both sets of results to determine the effects of music on the reading comprehension of the group.
Poll each individual. Provide the participants with a qualitative questionnaire that asks what they thought about the music playing. Reading these will provide you with information on whether they felt it was a positive or negative experience.