the chores? how do we keep from fighting? how do we have more sex? answer these questions and you have the key to the perfect marriage. but where do get these answers? oprah? dr. ruth? try alan greenspan. >> economics is the study of the allocation of scarce resources. what is more scarce in your marriage than time, energy, libido, love. >> reporter: the authors of "spousonomics" say the key to a life of love is economic analysis. take jack and jane in their chores. if jack has to do the laundry half the time, jane should, too, right? >> right, 50/50's fair. >> uh-huh. >> reporter: it might sound fair but economics says folly. >> if you're doing half and i'm doing half of each task, then the time we're spending on everything is actually greater than if we specialized in tasks. >> reporter: it's called comparative advantage. say it takes jack 30 minutes to do the laundry and 20 minutes to walk the dog. jane can do the laundry in 45