New Delhi, Dec. 2 -- India's GDP data has always flummoxed experts. Last week, the news of a 'C' rating by the International Monetary Fund (IMF), highlighting shortcomings in the data, baffled the public at large, who were unsure what to make of an impressive 8.2% growth performance in the July-September quarter.

While the GDP data issues are not new, what's new is the rating system by the IMF-started last year-that has brought to public attention what experts have been saying for close to a decade.

A 'C' rating means India's GDP data has "some shortcomings that somewhat hamper surveillance".

To begin with, the fundamental issue is the use of a base year from over a decade ago, specifically 2011-12. Besides that, opacity in the use of ...