This study tests the validity of long-run PPP by applying the cointegr
ation methodology of Johansen and Juselius (1990) to monthly exchange
rate and price data for eleven countries. The results reveal that in a
ll cases the theoretical PPP-vector [11 -1] or [11 -1, c] is not conta
ined in the cointegration space. This finding is inconsistent with str
ict long-run PPP. Alternatively, evidence from unrestricted tests show
s that, with one exception, one or two cointegrating relationships do
exist. Given the existence of tariffs, transportation costs, and diffe
rences in the construction of price indices across countries, PPP may
be consistent with a cointegrating vector other than [11 -1] or [11 -1
, c]. In fact, the widespread evidence of cointegration obtained from
the unrestricted tests suggests that the possibility of PPP for U.S. D
ollar exchange rates for the recent floating rate period should not be
dismissed.