The basic considerations in making assignments are to assure equitable distribution of caseload and avoid judge shopping. By statute, the chief judge of each district court has the responsibility to enforce the court's rules and orders on case assignments. Each court has a written plan or system for assigning cases. The majority of courts use some variation of a random drawing. One simple method is to rotate the names of available judges. At times, judges having special expertise can be assigned cases by type, such as complex criminal cases, asbestos-related cases, or prisoner cases. The benefit of this system is that it takes advantage of the expertise developed by judges in certain areas. Sometimes cases may be assigned based on geographical considerations. For example, in a large geographical area it may be best to assign a case to a judge located at the site where the case was filed. Courts also have a system to check if there is any conflict that would make it improper for a judge to preside over a particular case.