Seattle Zestimates are off by $40,000; now hundreds of data crunchers vie to improve Zillow’s model

Zillow says the gap between man and machine is narrowing in the quest to predict home values, but its Zestimates are still off by an average of nearly $40,000 for a house sold in Seattle today. Now a $1 million prize is being dangled to whoever invents a better housetrap.