Mortgage products offered by lenders haven’t changed much since the 1930s and are in a primitive stage, according to Robert Shiller, an economist who helped develop the Case-Shiller home price index. In a new paper published by Yale University’s Cowles Foundation for research in economics, Shiller pushes for greater innovation in the mortgage industry. He is currently a professor at Yale and for years has advocated a product he developed, “continuous workout mortgages,” to no avail ...