There is some brutal competition for retail deposits right now and I think the banks are getting sophisticated about balancing interest rates and consumers’ who satisfice versus those who optimize. They can probably afford to lose the latter.
Oooh that would be a good, and relatively simple, one to model. You could do the toy version without the interesting numbers and then tell people that they can datamine up the interesting numbers (propensities) and you'll predict the future under various strategies.
