Today’s post by Cynan Cleaver and Oliver Guest plots time series of these statistical moments for the hundreds of categories of 8‐Digit CPI components. As we discussed in our recent policy brief, lower headline inflation outcomes have not necessarily been associated with less inflation uncertainty. Positive skewness on average, indicates that while most items experience moderate price changes, a smaller number of items have large price increases that pull the average upward. A high standard deviation suggests wide variation in price movements across individual products, reflecting diverse inflationary pressures within the economy. Kurtosis spikes in the early 2010s, the period between late 2021 to 2022 and in 2025, reflecting, amongst other things, very large relative increases in some government‐related price categories and some food price categories. As discussed in our paper on the inflation targeting debate this impacts assessments of the appropriateness of policy settings, given the importance of supply shocks in the determination of inflation in South Africa.
