Tracking certain families in urban settings can be difficult–the names are often more common than you think. One way to help distinguish individuals is by their residence–every residence listed on a document. The key in connecting members of this Sullivan family from Pittsburgh was using the residences of the informants on death records, next of kin on draft registrations, etc. The individuals moved around, but the next of kin and informants were almost always living at the same address.
Not every family has that “one person who never moves,” but it is always advised to track every address for anyone listed on your relative’s documents. Those locations can be the key to separating out families and making connections where appropriate.