11  9  Papers that examine the pass-through issue include Gagnon and others (2011), Wright (2011), Krishnamurthy and Vissing-Jørgensen (2011), Swanson (2011), and Hancock and Passmore (2011). Primary mortgage rates, of course, are distinct from secondary-market rates for assets traded in centralized markets.
A variety of factors affect the wedge between the secondary MBS rate and the primary mortgage rate, and these factors, and hence the degree of pass-through, may vary over time. 10  See Kiley (2012) for a recent model that predicts a differential reaction of spending to changes in term premiums versus changes in the future path of short rates.