Dual filing is usually an issue when dealing with a discrimination complaint, although some Department of Labor issues can be filed with both the state and federal arm of the DOL. The two agencies involved in a discrimination dual filing are the federal EEOC and the state’s human rights department. In most states, the form you need to fill out to initiate a discrimination complaint allows you to automatically file in both the state and federal offices. If at all possible, check the box that allows an automatic dual filing.
Sometimes, though, because the EEOC may allow a longer time before actually filing the complaint or because the state has additional laws that cover more situations than the federal laws do, the complaint may only be filed with one agency. You will know that your discrimination case has been filed in both offices because both the EEOC and the state agency will assign the complaint a case number. So your single complaint will get two separate numbers that will be displayed on all correspondence from the agencies to you.
The priority issue is another one of those things that you can decide when you initiate the complaint. For an employment attorney, this decision is strategic, based on how backlogged the agencies are, who will provide voluntary mediation, who will help broker a settlement, or what the attorney wants to do with the case. If the attorney wants the case to end up in federal district court, the EEOC will take priority. If the attorney wants the case to stay in the state courts, the state agency will take priority.