
2 answers
Hi Erica,
Could you do a roll up field to the master/parent object and then use a formula field on the child to grab that information from the parent? I did notice this was listed as an idea on the IdeaExchange (link below). The comments on the idea mentioned using a workflow rule and a field update but that would be dependent on the child object being edited.
https://success.salesforce.com/ideaView?id=08730000000BpXI