To be clear, the cost of the program is about $13,000 per successful modification-- and, as Robert has mentioned, it's only natural that a percentage of the trial modifications aren't successful; these are borrowers who are in default or are nearly in default, and are under financial stresses.  The modifications that are not successful do not cost much because the incentives are not paid.

Now, do we save one foreclosure for each $13,000 spent?  No, because some people wo get successful modifications will later default and be foreclosed, and some people get modifications who wouldn't have defaulted.  But let's say that $20,000 is spent for each foreclosure averted-- I think that may actually be a decent bang for the buck, when you consider how much money the banks lose per foreclosure and what foreclosures do to a family's stability and what the negative effects on neighborhoods and property values.

After what we've been through in the past few years, I think "smashing successes" in housing are pretty much out of reach for the time being.  Everybody's still looking at just stopping the bleeding.