Cluster genealogy is an in-depth research method. Instead of researching one individual you research everyone associated with him/her. Instead of just a spouse and children, cluster genealogy would include neighbors, friends mentioned in letters, perhaps even a witness in a land dispute.
It wasn't uncommon for whole family groups (uncles, aunts, cousins) to all move together, so a neighbor could easily be a relative. Knowing relatives and neighbors who may have moved with your relative would make it easier to identify him in a new location.
