Unobtrusive measures are ways of studying social behavior without affecting that behavior.
They most often involve observing or recording indicators of what happened based on evidence that is left behind after that social behavior has taken place. For instance, unobtrusive measurement can be done by observing or recording the number of clients who successfully completed a treatment program on the basis of what their case records or files indicate. Case record studies are a common and important form of social work research. Many important studies have been done by primarily recording information from case records. Such studies include ones indicating whether an agency is providing the appropriate level of service for the cases assigned to it, whether particular programs are effective in providing treatment, whether some forms of treatment are more effective than others, whether some groups of clients are more likely to receive favorable treatment, etc.