Advertisement The purpose of a family mission statement is really to help you and whoever else you parent with articulate your big, high-level values. But Oster doesn’t see it as simply a lofty expression of ideals. Instead, it’s a practical document that will help your family sort through parenting decisions every day. “When I talk about creating the family Big Picture, I’m talking about these overall principles,” Oster writes in “The Family Firm.” “But I’m also talking about confronting, ‘What does Thursday night look like?’” To start, everyone who is a parenting sta...