Retail Prices Index
The Retail Prices Index is a UK consumer-price measure with coverage and methods differing from CPI and CPIH. It includes items such as mortgage interest payments and remains relevant to some contracts and historical comparisons. Its methodological shortcomings mean it should not be treated as interchangeable with other inflation indices. When using an index-linked payment, apply the index and timing specified by the contract rather than choosing the most convenient measure.
Worked example
A contract specifies an increase using a particular RPI annual change. The preparer identifies that published series and reference month instead of substituting the CPI rate, even if CPI is discussed more often in general commentary.
Common mistake
Do not present RPI as the universal measure of UK inflation or infer that identical base-year values make different indices equivalent.
Where it appears in your exams
| Qualification | Exam | Relationship | Period |
|---|---|---|---|
| ACCA | BT | Supporting | September 2026–June 2027 |
| FIA | FBT | Supporting | September 2026–June 2027 |