Having worked with young people who offend for some time, I questioned the effectiveness of interventions because the young people may not have had enough emotional understanding to process the sessions. For example, how can a young person who demonstrates anger management difficulties learn control without an appreciation of how their own emotions work, or even what they might be? In my PhD, I set out to discover whether young people in the criminal justice system had a level of emotional intelligence related in some way to their propensity to offend using an already existent questionnaire, validated for use with young people. Because I had to ask for colleagues' help with the questionnaire completion, consistency could not be ensured in its delivery with young people, so the returned questionnaires showed serious discrepancies. Statistical analyses revealed where these inconsistencies lay, and helped mitigate their effects for the purposes of my study. However, my discoveries also formed the basis of important principles for using this kind of questionnaire with young people, especially those with more communication difficulties and lower literacy levels than the general population. [This content is provided in the format of an e-book.]