One hypothesis for the flat Phillips curve is that central banks have been so effective in anchoring inflation expectations that tightening resource utilization is no longer transmitted to price inflation.
11 Another possibility is that structural factors such as administrative changes to health care costs, globalization, or technological-enabled disruption have been dominant in recent years, masking  11  For evidence that inflation expectations may have played a role in flattening the Phillips curve, see Damjan Pfajfar and John M. Roberts (2018), “The Role of Expectations in Changed Inflation Dynamics,” Finance and Economics Discussion Series 2018-062 (Washington: Board of Governors of the Federal Reserve System, August), https://doi.org/10.17016/FEDS.2018.062.