Pronab Sen, India's chief statistician and secretary, MOSPI, spoke to Pragya Singh. Excerpts:
Why is the new index taking so long and why are inflation numbers always revised?
Technically, data submission by industry is not entirely voluntary, but we haven't yet invoked regulations to force compliance or impose fines. So, the price data we get from industry is very poor and trickles in over several weeks...and we have to update the index.
How reliable is the advanced estimate?
Only 18-20 per cent of quotations sought from manufacturers are received in time to make advance estimates of wpi inflation, though our estimates are pretty okay for agriculture and most primary products. In the second revision, 65-70 per cent of primary articles find their way.
An IMF report has said inflation is lower than we think if we adjust seasonal variations. What do you make of it?
Seasonally adjusted data helps compare inflation in a particular period with the immediately preceding period—a week compared to the one just...