¹⁹All the authors cited above used U.S. data. Nielsen and Vissing-Jorgensen (2006) used Danish data and estimated $σ2 = 0.005 ψ$ and $σ2 = 0.015 ξ$ . It would be reasonable to interpret their estimates as the lower bounds for the U.S., given that their administrative data is well-measured and but that Danish welfare is more generous than the U.S. system.