You should determine the test groups based on the needs and scope of your experiment, but you should select test groups that reduce your research bias. During your research design phase, determine how you will select subjects for your study, and follow your research design decisions in your testing. Select research limits carefully, such as testing groups of people based on their age, gender or group affiliation. Include a detailed account of how you chose your research subjects and the qualifications that you chose for each, such as testing only boys or girls from the 15 to 20 age group.
Avoid using clinical or professional language in your questions. For instance, instead of asking someone if they have a formal respect for justice, describe a moral choice that relates to the nature of justice and allow your subject to describe how they react to the choice. You can also layer your questions by asking a subject a series of follow-up questions, such as asking the question, "You see a classmate pushed to the ground by another student, what do you do?" If she responds by saying that she would tell the student to stop, you can ask, "You see the student turn to you as he begins to threaten you, what do you do?" Your question, which initially asked your subject to question her idea of justice, is now asking her to consider her sense of self-preservation.
Moral development experiments can cover a range of possible topics. These include determining the age at which people develop specific moral understandings, identifying where people learn their moral ideals or whether people develop different moral ideals at a different rate. You can focus your research on older, more developed research subjects or focus on younger and still developing research subjects. Another topic option is for you to compare the responses of people from different backgrounds, such as age, gender, socioeconomic status or region.
Your first responsibility while performing a moral development experiment is to keep your test subjects identities anonymous. You can include identifying points that are significant to your research, such as their age or gender, but you should omit any personal identifiers, such as phone number, name or home address. Also, if you are testing people who are under the age of 18, you are responsible for getting written permission from their parents before testing them or including them in your research.