Why a household’s bills can rise faster than the inflation rate
The consumer price index combines many prices using spending weights.
A consumer price index tracks changes in the prices of a basket of goods and services. Its weights reflect how households spend in the aggregate, so a widely purchased category can have more influence than a smaller one.
A household can experience a different change in living costs if it spends more on categories whose prices are rising faster. The OECD's explanation describes how the index is constructed and why it is useful for comparing changes over time, even when individual budgets differ.