Amid the hubbub of recent inflation figures we may have skipped over the subtleties of the different measures now in use.  After all, RPI is at 5.0% is the same as RPIX, while both are clearly running ahead of CPI which is at 3.2% at the end of June. 

Meanwhile, Chancellor of the Exchequer George Osborne has pointedly decided to change the index linking of benefits, tax credits and public service pensions from RPI to CPI from April 2011.

But what’s the difference between these measures anyway?  Indeed, are the subtleties of each really worth the column inches they get in the media?  And what about the other indices that struggle to get a look in?  How is the RPIY doing these days?  Is the TPI looking healthy?  Or even the CPI-CT? And, more importantly, do any of these acronyms really matter?

The Office for National Statistics (ONS) produces a comprehensive guide in the form of the excellent Consumer Price Indices Technical Manual - 2010 Edition.  If you are a little short on time we would recommend their booklet Consumer Price Indices – A brief guide.