For many of the disadvantaged and vulnerable families we work with, CPI and RPI are just random abbreviations which they might never have heard of.
They're about to learn to their distress that these abbreviations could have profound impacts on their family finances and their ability to support their children and provide a stable home.
From April this year, welfare benefits were linked to the Consumer Price Index instead of the Retail price Index as previously, a move widely predicted at the time to reduce the value of benefits over time given that the RPI has generally risen faster than the CPI.
This seemed a mean-minded enough prospect to those of us working with poor families. However now that the CPI is rising more steeply than forecast the chancellor is looking to claw back even this miserable value linkage. Instead a linkage to average earnings is being mooted, the argument that many of those in work are suffering in pay freezes.
This ignores the way in which the value of out-of-work benefits have been steadily downgraded in value over time while other benefits have been hacked away by welfare reform, including the removal of the Sure Start maternity grant for a second child and slashing of help available for childcare to 70% coverage
Since 1997, I have been Chief Executive of Family Action a charity providing early intervention services and grants to very disadvantaged families beset by issues such as mental health, domestic violence, substance misuse, worklessness and severe financial hardship. So I and my practitioner colleagues regularly witness the impact that breadline welfare incomes have on disadvantaged families' ability to provide a decent home and fill the kitchen cupboards regularly.
Applicants to our grants fund commonly request carpets because their babies are crawling on bare floor boards; or curtains because their children are undressing in bedrooms with windows open to public view; or a wardrobe because their children currently store their clothes in a bin bag.
Both adequate services and welfare support are vital for these families so that they can turn things around. The pressures they're facing have only got tougher over recent years. Austerity Britain is not a happy place for these families caught between a Government slashing welfare support and local authorities forced to choose between services due to budget cuts.
Media reports this week that the Government are moving the goalposts on benefit increases will only make matters worse. As this insightful blog by our Policy and Campaigns Officer Michael Kelly on our own State of Welfare blog points out, families are already struggling on benefits which are barely at subsistence levels.
In addition to the benefit linkage to CPI so far this year, food and fuel inflation heap on the misery. Never mind the squeezed middle, the poorest families are being strangled and smashed by benefit cuts and price hikes. One mum even told us this week that she has warned her children she may have to cancel Christmas because was so worried about fuel bills dropping on the doormat in January.
That's why these latest attempts by the Treasury to cut the benefit bill by stealth are so worrying. They could literally mean the difference between putting food on the table and parents being able to support their kids. And it could also mean the Government failing miserably to achieve the Child Poverty targets as the Institute for Fiscal Studies recently suggested.
The Prime Minister has repeatedly said that he wants his Government to be the most "family friendly" ever. We know from our work that strong families need good friends to support them sometimes and give them a helping hand.
It's time for David Cameron to prove he's a family man and for him to kick his Number 11 neighbour's policy of stripping back financial support even further into the long grass.