Drawbacks of PPP: The biggest one is that PPP is harder to measure than marketbased rates.
The ICP is a huge statistical undertaking, and new price comparisons are available only at
infrequent intervals. Methodological questions have also been raised about earlier surveys.
Between survey dates, the PPP rates must be estimated, which can introduce inaccuracies into
the measurement. Also, the ICP does not cover all countries, which means that data for missing
countries must be estimated.