Across the years, it became evident to me that there some metropolitan areas recieve different metfips codes in some samples, sometimes due to one are being incorprated in another, sometimes an area can be separeted into several, and sometimes seemingly at random. In order to compare data in the metropolitan level, one needs to designate a unique and stable code for each metropolitan area, but I failed to find any data that can help me to connect the different codes. Is there some sort of table or file that documents the change in codes of each metropolitan area over the years?
Thank you.