This is because the information and data they produce are very detailed, often very specific to a certain individual or group in the analysis. The data produced is primary source and tends to be plentiful and expensive, but means the information helps understand different feelings and mutations. Many methods are used in case studies, for example journaling. This can be done by the participant themselves and/or their guardian or carer and helps the researcher gain insight into daily life and how the participant responds to their environment. They may also use interviews during which close family and friends, or even colleagues and professionals involved with the participant, have the opportunity to explore their perceptions and opinions regarding the participant as well as any concerns they may have. Using these methods, over time the researcher can bring together their information and results and produce what then constitutes a “case”. ».