People's names are a key in our database structure so different people must have different names. If they have the same name, we have to use something to make them different, in these cases we use Roman numerals.
We make two different types of uses of Roman numerals:
1. When they are not in parentheses, like Lloyd Ahern II, this is an actual part of someone's name. In Lloyd's case, his father has the same name, so the familial relation is represented by the II. When some people more commonly or very consistently use "Jr." we do not use a roman numeral as the junior notation makes the names different.
2. When they are in parentheses, that is an internal notation for the database. We may have a costume designer, a director, and an actor all named John Smith, none of whom are related. If we did not separate them by use of parenthesized Roman numerals--the (I) and (II), etc., that you see--their credits would all be combined, meaning there would be one John Smith with all of their credits instead of three John Smiths with the proper credits for each.
How are numerals ordered?
When there is more than one name with the exact same text, Roman Numerals are assigned automatically. These are usually assigned chronologically (i.e. in the order the names are added to IMDb), they do not reflect the popularity of the name - for example, popular actress Jennifer Lawrence is referenced in the database as Jennifer Lawrence (III).
Can I change my numeral?
To avoid confusion among our users and to prevent potential loss of data due to unnecessary corrections, we do not change or reorder roman numerals once they have been assigned, except as dictated by internal technical requirements.