What explains the plunge in core inflation?

In contrast to the sudden weakness in core inflation a few years ago, the latest plunge in core PCE inflation cannot be explained by idiosyncratic factors. Instead, it reflects a moderation in unit labour cost growth, which will persist for some time. With core inflation now well below the Fed’s 2% target and heading lower, economic growth may not need to weaken by much to prompt the Fed to cut interest rates.