Is the Phillips curve dead, or simply dormant? The Phillips curve traces out the relationship between the degree of slack in the labour market (unemployment) and the rate of change in wages, and hence in prices. After nearly a century in which this relationship held well (1870–1960), it broke down in the 1970s as both unemployment and inflation rose (stagflation), owing to a failure to take proper account of expectations of future inflation. More recently, the relationship has again puzzled economists, since inflation has remained quite steady and low despite large swings in unemployment, up in 2009/2010 and down since then. Goodhart and Pradhan discuss six possible (partial) explanations, which are: i. The Phillips curve is defunct; ii. Expectations are all that matter; iii. Successful monetary policies; iv. A changing structure of employment; v. Growing weight on global factors; vi. A shifting NRU. The final explanation, mostly ignored in the conventional analysis thus far, likely explains more of the Phillips curve puzzle than the rest in their view.