Instead, neutral has to be inferred from the economic information that we have available. Neutral can also change over time, and it may not always be clear whether the change is caused by cyclical movements or an underlying trend in real economic conditions.
For an investigation into whether mismeasurement may be responsible for some of the slowing in productivity growth, see Byrne, Fernald, and Reinsdorf (2016) and Syverson (2016). For an optimistic outlook on future productivity growth, see Baily, Manyika, and Gupta (2013). BIS central bankers’ speeches  5  Fernald, John (2014).