Re-Examining the South African Reserve Bank’s Policy Reaction Function Using the NARDL Model

The 3–6 percent inflation target is a policy rule used by the South African Reserve Bank (SARB) to fulfil its statutory obligation of ensuring a low and stable inflation environment and its policy reaction function assesses how the Reserve Bank responds to deviations of inflation from its target. We rely on nonlinear autoregressive distributive lag (NARDL) models to estimate the asymmetric preferences which the Reserve Bank has to inflation deviations during rising and falling episodes of inflation. Using quarterly data spanning from 2002:q1 to 2021:q4, we estimate the policy reaction functions using 7 disaggregated measures of inflation to capture the heterogeneity in the formation of price expectations. We further segregate our data into two sub-periods, corresponding to the pre-crisis and post-crisis era, as a robustness exercise. Overall, our findings indicate that in the post-crisis era the SARB (i) has become more responsive to inflation, output fluctuations and exchange rates and (ii) has responded more aggressively to rising inflation than falling inflation.