Input (grade 13): While at Penn, Phelps' research focused mainly on the link between employment, wage setting and inflation, leading to his influential 1968 paper "Money-Wage Dynamics and Labor Market Equilibrium".
Output (grade 9): While at Pennsylvania, most of Phelps' research was on the links between employment, wages and inflation. He wrote about this in 1968: "Money-Wage Dynamics and Labor Market Equilibrium".