This repo collects puzzling evidence and open questions in macroeconomic research. It aims to be a compilation of the contradictions between economic theory and the empirical evidence. Hopefully it will help us all (and motivated junior researchers) to focus on the important questions and the big picture. As such it has some similarity to the list of Hilbert's Problems.

Definition of a puzzle in this context:

A puzzle is a contradiction between theoretical conjectures and empirical evidence

This list is thought to be constructive and not intended to be a one-sided critique on macroeconomics/DSGE models/rational Expectations/parapsychic mind control as a whole. Please be neutral and concise. If you want, you can add details like literature or links to potential solutions in a separate file.

• The Forward Guidance Puzzle: standard DSGE models tend to grossly overestimate the impact of Forward Guidance on the macroeconomy (Del Negro, Giannoni and Patterson, 2015, FED NY Working Paper)
• The Rational Expectations Puzzle: survey evidence contradicts the rational expectations hypothesis (Greenwood and Shleifer, 2014, Review of Financial Studies)
• The Flat Phillips Curve: the coefficient of the NK-PC as well as regression coefficients of inflation on unemployment will be very close to zero (e.g. Ball and Mazumder, 2011, NBER Working Paper)
• The Monetary Transmission puzzle: intertemporal substitution is a too simplistic view on the monetary transmission mechanism (e.g. Jappelli and Pistaferri, 2010, Annual Review of Economics)
• The bond premium puzzle: macro models cannot explain the large and variable premium on long-term vs short-term bonds (Rudebush and Swanson, 2008, JME)
• The Shimer puzzle: basic search-and-matching models cannot explain the volatility in unemployment given the observed volatilty in labor productivity (Shimer, 2005, AER)
• The Price Puzzle: in many studies, the Fed Fund rate is positively correlated with inflation (Bernanke and Blinder, 1992, AER)
• The Equity Premium Puzzle: Macro models require an implausibly high degree of risk aversion to explain the premium of stocks over "safe" bonds (Mehra and Prescott, 1985, JME)

See here on how to add an item to the list, and have a look at (and admire) the list of contributors.