So-called New Keynesian analysis has focused on or developed all of these concepts except

• A. Real business cycle theory.
• B. The ability of households and firms to have and act on perfect information.
• C. Implicit labor contracts
• D. Efficiency wages

Answer: (A)

New Keynesian analysis centers on how nominal rigidities and information frictions shape how the economy responds to shocks. It explains why prices and wages don’t adjust instantly and how that slow adjustment can sustain unemployment and output gaps. Mechanisms like implicit labor contracts and efficiency wages are used to model why wages won’t instantly fall or rise in line with demand, which helps account for persistent unemployment and real effects of demand changes. Real business cycle theory, by contrast, emphasizes that fluctuations are driven by real shocks and assumes flexible prices and perfectly informed agents who clear markets, so it’s not the focus of New Keynesian work. That contrast is exactly why the concept not developed by New Keynesian analysis is real business cycle theory.