A CPI measures the changes in the cost of a fixed and representative basket of goods and services. This involves weighting together aggregated prices for different categories of goods and services so that each takes an appropriate share to reflect the budgets of the households covered by the index.
The expenditure weights are obtained from the Household Income and Expenditure Survey (HIES) conducted periodically by the Namibia Statistics Agency. The inflation figures from the CPI represent a weighted average of price changes.
The use of expenditure weights, from the HIES, in a CPI is often referred to as a CPI based on the concept of plutocratic weights as they are based on the total expenditure of the households in the scope of the CPI. This is consistent with UN guidelines for a general measure of inflation.