A recent research note by JPMorgan examines the divergence between CPI - not the new one, because of its short life, but the old CPI for industrial workers - and the WPI. The analysis suggests that the predominant cause of the large divergence is food. This results from both the much larger weight for food in the CPI and, importantly, the composition of the basket in each index. The latter has a larger share of food items whose prices have been rising relatively fast. What are the implications of this finding? On the one hand, it validates the use of the WPI as a benchmark that captures the inflationary conditions that consumers are experiencing outside of food. On the other, however, to the extent that food prices are an important influence on the inflationary expectations of a large proportion of the labour force, high CPI inflation could pose risks for entrenchment of expectations and persistence of inflation. So, policy should prioritise inflation management until this number descends to reasonable levels. In short, there is still ambiguity.
But beyond this relatively long-term pattern, comparisons between the specifics of the new CPI and the WPI do raise some concerns. For example, core inflation, or inflation in non-food manufactured products, appears to have declined far more significantly for the WPI than for the new CPI. Of course, the goods covered by the two are quite different, but even if more disaggregated comparisons are made, discrepancies are observed. Data quality could, of course, be one reason for this, but does it also reflect some structural rigidities in the retail system, which is not allowing lower wholesale prices to transmit through to the consumer? Until the much-desired clarity on this finally emerges, making monetary policy is like driving a vehicle with two speedometers. You can simultaneously be challaned for driving too fast and too slowly!