Cheung et al. (2004) use a vector error correction model that allows different speeds of convergence for nominal exchange rates and relative prices toward PPP. With the current float monthly data for five countries, they argue that the sluggish PPP reversion is primarily driven by nominal exchange rate adjustment rather than price adjustment, which is at odds with the conventional sticky-price models. Major findings of this paper are twofold. First, we show that it may be inappropriate to use short-horizon high frequency data in vector error correction models, even when both the nominal exchange rate and the relative price are not weakly exogenous. Second, using a long-horizon annual data set for 11 countries vis-?vis the US, we find a significantly important role of relative prices in real exchange rate dynamics.