Investors and policymakers continue to wrestle with the economic impact of the dollar’s rise. The Federal Reserve has argued that the dollar’s appreciation acts as a headwind on exports and dampens imported inflation. At the same time, despite the dollar’s appreciation and the fall in oil prices, core inflation rose steadily last year.

Core CPI rose from 1.6% at the end of 2014 to 2.1% at the end of 2015. The core PCE deflator lagged, but the after bottoming last July below 1.26%, it finished the year near 1.41%. 

Fed officials have a nuanced understanding of the dollar. On one hand, the share of exports in the US economy are less than half of Germany’s for example, and much of what the US imports is invoiced in dollars, the greenback’s exchange rate is not often a particularly important variable in the policy-making equation.

However, when there is a sharp dollar move, it becomes more salient. Since mid-2014, the nominal trade-weighted dollar index that the Federal Reserve tracks by nearly a quarter through the end of last month. Adjusted for inflation, the dollar’s appreciation was a little less than 20%. 

On the other hand, Fed officials argue that impact of the dollar’s rise is transitory. By that, officials direct investors’ attention to the rate of change. The economic is largely driven by the pace of change, not the level. The level may not be transitory, but the rate of change is unlikely to be sustained. 

That means the impact on prices and exports will moderate in time. For example, in the nine-month stretch from mid-2014 through Q1 2015, the nominal trade-weighted dollar appreciated by 19%. The impact may still linger then in Q1 16, but then it should fade.  Since last March, the dollar has risen almost 5.5%, which is not nearly as riveting.

Part of the challenge for investors is that the Federal Reserve’s trade-weighted measures of the dollar are updated monthly. However, there is a real-time measure that is nearly as good. It is the Bank of England’s measure of a nominal trade-weighted dollar index.