A NOTE ON THE TRIMMED MEAN MEASURE OF CORE INFLATION IN SOUTH AFRICA

This paper constructs and analyses the properties of a trimmed mean inflation rate for South Africa. Based on an analysis of the distributions of the consumer price index component price changes, a measure is constructed that provides an estimator of core inflation, which may be particularly useful to policymakers in an inflation‐targeting environment. The trimmed mean estimator focuses on the price movements of individual components that have a strong bearing on the current and future trend of the headline inflation rate, allowing monetary policy to be directed at the persistent or underlying sources of inflationary pressures.     

Measuring Core Inflation in South Africa

Measures of core inflation convey critical information about an economy. They have a direct effect on the policymaking process, particularly in inflation‐targeting countries, and are utilised in forecasting and modelling exercises. In South Africa, the price indices on which inflation is based have been subject to important structural breaks following changes to the underlying basket of goods and the methodology for constructing price indices. This paper seeks to identify a consistent measure of core inflation for South Africa using trimmed means estimates, measures that exclude changes in food and energy prices, dynamic factor models, and wavelet decompositions. After considering the forecasting ability of these measures, which provide an indication of expected second‐round inflationary effects, traditional in‐sample criteria were used for further comparative purposes. The results suggest that wavelet decompositions provide a useful measure of this critical variable.     

Revisiting the Exchange Rate Pass‐Through to Inflation in Africa’s Two Largest Economies: Nigeria and South Africa

This paper revisits the exchange rate pass‐through (ERPT) to inflation in Nigeria and South Africa by incorporating structural breaks and using time series variables, namely the consumer price index, nominal effective exchange rate, gross domestic product, and crude oil price. Based on the Maki cointegration test and a flexible estimation approach of the Autoregressive Distributed Lag (ARDL) model, our empirical evidence suggests that the long‐ and short‐run ERPT to inflation is complete for Nigeria, while for South Africa it is incomplete both in the long run and short run. This result indicates that prices are stickier in South Africa compared to Nigeria. The comparison between Nigeria and South Africa confirms the role of inflation targeting and central bank credibility on the ERPT. The results divulge further that output growth in Nigeria increases inflation in the long run while it is anti‐inflationary in the short run. For South Africa, the effect of output growth is negatively insignificant. In addition, the long‐run effect of oil price is negative and significant for Nigeria, while for South Africa the short‐run effect of oil price is positive and significant. Therefore, the findings of this paper will assist the monetary authorities to achieve monetary policy objectives.     

INFLATION PERSISTENCE AND CORE INFLATION: THE CASE OF SOUTH AFRICA

This paper analyses the persistence of inflation in South Africa since 1981. A measure of the persistence of inflation provides important information about the impact of shocks on the economy over time. This information can be extremely useful for the purpose of setting monetary policy, especially in a small, open economy like South Africa. In addition, an estimate of persistence at the disaggregate level helps in the identification of the main drivers of aggregate inflation. This information is useful in deriving a core measure of South African inflation, which outperforms some of the more readily available core measures in identifying the underlying inflationary pressures in the economy.     

Price‐Setting Behaviour in Lesotho: Stylised Facts from Consumer Retail Prices

This paper documents some of the main features of price‐setting behaviour by retail outlets in Lesotho over the period March 2002 to December 2009. These features include the frequency, size, duration and synchronisation of price changes. In addition, the paper compares price‐setting behaviour in Lesotho and South Africa using a comparable set of products. The findings reveal considerable heterogeneity in price‐setting behaviour across products, outlets, locations and time. Variations in inflation are strongly correlated with the average size of price changes, but rising inflation raises the frequency of price increases and reduces the frequency of price decreases. Price decreases constitute an important determinant of inflation movements. Surprisingly, the frequency and size of price changes in Lesotho differ substantially from those in South Africa, despite the presence of common retail chains and their joint membership in a customs union and common monetary area. These findings open up opportunities for further research into the sources of heterogeneity across products and Lesotho and South Africa in the setting of prices.     

Global food prices and monetary policy in an emerging market economy: The case of India

This paper investigates a perception in the political debates as to what extent poor countries are affected by price movements in the global commodity markets. To test this perception, we use the case of India to establish in a standard SVAR model that global food prices influence aggregate prices and food prices in India. To further analyze these empirical results, we specify a small open economy New-Keynesian model including oil and food prices and estimate it using observed data over the period 1996Q2 to 2013Q2 by applying Bayesian estimation techniques. The results suggest that a big part of the variation in inflation in India is due to cost-push shocks and, mainly during the years 2008 and 2010, also to global food price shocks, after having controlled for exogenous rainfall shocks. We conclude that the inflationary supply shocks (cost-push, oil price, domestic food price and global food price shocks) are important contributors to inflation in India. Since the monetary authority responds to these supply shocks with a higher interest rate which tends to slow growth, this raises concerns about how such output losses can be prevented by reducing exposure to commodity price shocks.     

DYNAMIC TIME INCONSISTENCY AND THE SOUTH AFRICAN RESERVE BANK

This paper derives the econometric restrictions imposed by the Barro and Gordon model of dynamic time inconsistency on a bivariate time-series model of consumer price index (CPI) inflation and real gross domestic product (GDP), and tests these restrictions based on quarterly data for South Africa covering the period of January 1960-April 1999, i.e. for the pre-inflation targeting period. The results show that the data are consistent with the short- and long-run implications of the theory of time-consistent monetary policy. Moreover, when the model is used to forecast one-step-ahead inflation over the period of January 2001-February 2008, i.e. the period covering the starting point of the inflation-targeting regime until date, we, on average, obtain lower rates of inflation. The result tends to suggest that the South African Reserve Bank perhaps needs to manage the inflation-targeting framework better than it has done so far.     

On the Sources of Inflation in Kenya: A Model‐Based Approach

We develop a semi‐structural new‐Keynesian open‐economy model – with separate food and non‐food inflation dynamics to study the sources of inflation in Kenya in recent years. To do so, we filter international and Kenyan data (on output, inflation and its components, exchange rates and interest rates) through the model to recover a model‐based decomposition of most variables into trends (or potential values) and temporary movements (or gaps) – including for the international and domestic relative price of food. We use the filtration exercise to recover the sequence of domestic and foreign macroeconomic shocks that account for business cycle dynamics in Kenya over the last few years, with a special emphasis on the various factors (international food prices, monetary policy) driving inflation. We find that while imported food price shocks have been an important source of inflation, both in 2008 and more recently, accommodating monetary policy has also played a role, most notably through its effect on the nominal exchange rate. We also discuss the implications of this exercise for the use of model‐based monetary policy analysis in sub‐Saharan African countries.     

DETERMINANTS OF INFLATION IN GHANA: AN EMPIRICAL INVESTIGATION

This paper provides an empirical analysis of the factors accounting for inflation dynamics in Ghana using the bounds test and other econometric approaches. We find that real output, nominal exchange rate, broad money supply, nominal interest rate and fiscal deficit play a dominant role in the inflationary process in Ghana. To the extent that output growth by far has the strongest impact on inflation, targeting supply‐side constraints will help moderate price inflation. The paper concludes that inflation in Ghana is explained by a combination of structural and monetary factors consistent with prior studies.     

MEASURING INFLATION CREDIBILITY: RESULTS OF A FIRST REPRESENTATIVE SOUTH AFRICAN SAMPLE

This study reports the measurement of inflation credibility of a representative sample of the South African population in terms of an inflation credibility barometer. The barometer is an instrument measuring the degree of acceptance of the accuracy of historic inflation figures. These research results serve as a benchmark for South Africa, as similar measurement of a representative sample has not been undertaken before. The sampling results show little public understanding of the rate of inflation and its measurement of average price increases experienced by an average household. As generally accepted international benchmarks for successful central-bank communication strategies do not exist, the application of the methodology reported in this paper can improve the effectiveness of central bank communication aimed at improving the general knowledge about inflation.     

The role of import prices in flattening the Phillips curve: Evidence from Korea

Are global inflation synchronization and the flattening of the Phillips curve across the globe related? The globalization hypothesis has been proposed to explain the relationship but questions remain on its quantitative role. Focusing on South Korea, one of Asia-Pacific supply chain hubs, this paper investigates the extent to which import prices affect domestic price inflation over the period between 2002 and 2020. Specifically, we conduct the regression decomposition method to identify major sources of variation in domestic inflation, followed by a subsequent set of comparative analyses across various inflation forecasting models. Our findings confirm a tight link from import prices to domestic prices, with a 10pp increase in IPI inflation passed onto PPI and CPI inflation by 3.9pp and 3.4pp over time, respectively. The main finding of this study is consistent with the recent global inflation surge that has been driven largely by imported food and energy price channels.     

Inflation in developing Asia

Inflation emerged as the single biggest macroeconomic challenge confronting developing Asia during 2007–2008, although inflationary pressures have abated since the second half of 2008 due to the global crisis. This paper empirically examines the relative importance of different sources of inflation in developing Asia. In particular, it tests the widely held view that the region's inflationary surge during 2007–2008 was primarily the result of external price factors such as oil and food shocks. Our central empirical result is that, contrary to popular misconception, Asia's inflation is largely homegrown and has arisen due to excess aggregate demand and inflationary expectations, rather than external price shocks. This suggests monetary policy will remain a powerful tool in fighting inflation in Asia, as well as in defusing the risks of deflation.     

Revisiting the Phillips curve for India and inflation forecasting

This paper focuses on modeling and forecasting inflation in India using an augmented Phillips curve framework. Both demand and supply factors are seen as drivers of inflation. Demand conditions are found to have a stronger impact on non-food manufactured products (NFMP) inflation vis-a-vis headline wholesale price inflation; moreover, NFMP inflation is found to be more persistent than headline inflation. Both these findings support the use of NFMP inflation as a core measure of inflation. But, the impact of global non-fuel commodities on NFMP inflation is found to be substantial. Inflation in non-fuel commodities is seen as a more important driver of domestic inflation rather than fuel inflation. The exchange rate pass-through coefficient is found to be modest, but nonetheless sharp depreciation in a short period of time can add to inflationary pressures. The estimated equations show a satisfactory in sample as well as out-of-sample performance based on dynamic simulations. Nonetheless, forecasting challenges emanate from volatility in international oil and other commodity prices and domestic food supply dynamics.     

AN ANALYSIS OF INVENTORY INVESTMENT IN SOUTH AFRICA

This paper describes the evolution of inventory investment in South Africa over the past two decades, and identifies the factors influencing inventory investment over this period. An econometric model of inventory investment in South Africa, based on the production smoothing approach, is constructed. The results of the model indicate that actual sales, production, unfilled orders, price levels, interest rates and expected sales have an influence on the evolution of inventory investment. These variables are directly or indirectly influenced by macroeconomic policy decisions and through their influence on inventory investment they also influence changes in gross domestic product. Therefore, prior information on the factors that influence inventory investment contributes to explaining changes in gross domestic product and may help to prepare more accurate short‐term forecasts of overall economic activity.     

Inflation in South Africa: An Assessment of Alternative Inflation Models

We consider the relative empirical performance of a range of inflation models for South Africa. Model coverage is of Phillips curve, New Keynesian Phillips curve, monetarist and structural models of inflation. Our core findings are that the single most robust covariate of inflation is unit labour cost. We further decompose unit labour cost into changes in the nominal wage and real labour productivity. The principal association is a strong positive relationship between inflation and nominal wages, while improvements in real labour productivity report only a relatively weak negative association with inflation. Supply‐side shocks also consistently report an association with inflation. As to demand‐side shocks, the output gap does not return a robust statistical association with inflation. Instead, it is growth in the money supply and government expenditure which return robust and theoretically consistent associations with inflationary pressure.     

China's impact on South African trade and inflation

There has been much controversy about the impact of Chinese growth on the rest of the world. It is generally accepted that China has a dampening effect on global inflation through the supply of cheap products. On the other hand, imports from China could displace domestic production and hence have adverse effects on economic growth and employment. Thus, the question of whether a country benefits from trading with China is a country-specific issue. The results in this paper indicate that limited short-term costs have resulted from the strengthening of trade relations between South Africa and China. As far as inflation is concerned, the paper does not find convincing empirical evidence at the aggregate level for inflation in China leading to domestic price changes. At the disaggregate level, however, there appear to be stronger sector-specific linkages between prices in China and South Africa.     

THE SOUTH AFRICAN PHILLIPS CURVE: HOW APPLICABLE IS THE GORDON MODEL?

Is there a Phillips curve relationship present in South Africa and if so, what form does it take? Traditionally the method to establish whether or not there is a relationship between the output gap and the change in inflation is merely to regress the latter on the former. This yields the well‐known augmented Phillips curve. However, Gordon has argued that this specification of the Phillips curve produces biased results. Instead, he puts forward and estimates successfully for several industrialised countries his so‐called triangular model that tests for hysteresis and inertia in the behaviour of inflation, as well as the impact on inflation of changes in the output level. This paper considers whether or not Gordon's triangle model is applicable to South Africa, i.e. are hysteresis and inertia present in South Africa? In addition, in an attempt to find a better estimation of the output gap, the paper also experiments with alternative ways to estimate the long‐run output level, including the standard HP‐filter, as well as a production function approach.     

ON INFLATION

There is currently much more common sense in the South African inflation debate than a few decades ago. In particular, the South African Reserve Bank exhibits a pragmatic, eclectic approach to inflation (as reflected in its bi‐annual Monetary Policy Reports). This is in stark contrast to the narrow, monetarist‐type thinking that tended to dominate during the 1980s. This paper is an attempt to contribute to the debate by highlighting a few issues, including the widespread substitution of the CPI by the CPIX, the fact that inflation is a process, the need to combat inflation, the causes of the decline in inflation in South Africa and the essential features of an inflation‐targeting framework for monetary policy.     

THE SENSITIVITY OF SOUTH AFRICAN INFLATION EXPECTATIONS TO SURPRISES

Price stability is widely recognised as the primary goal of modern monetary policy, and the management of private sector inflation expectations has become an essential channel through which this goal is achieved. This evaluation aims to improve the understanding of how the sensitivity of private sector inflation expectations to macroeconomic surprises in South Africa compares internationally, as this provides an indication of the contribution of monetary policy in South Africa to anchoring inflation expectations. If a central bank is credible, the financial markets should react less sensitively to macroeconomics surprises, because they trust the central bank to manage these incidents and achieve the objectives they communicated over the medium to long term. In this paper, the methodology of Gurkaynack et al. is adopted in order to measure the sensitivity of South African inflation expectations to surprises. A comparison of South Africa's results with those of countries in the original studies supports the contention that the SARB (South African Reserve Bank) has encouraged inflation expectations to be relatively insensitive to macroeconomic surprises, and offers support for the inflation-targeting framework as a means to help anchor inflation expectations.     

INTERNATIONAL LESSONS FOR THE PROPERTY PRICE BOOM IN SOUTH AFRICA

South Africa appears to share some of the characteristics (property price boom, easing of monetary policy, strong domestic demand growth) of asset price booms in industrial countries that were followed by a period of weak growth. The international experience suggests that a number of practical obstacles need to be overcome before a more proactive role for monetary policy is warranted. However, a larger variety of available mortgage contracts, including longer‐term fixed‐rate contracts, should allow for a more efficient allocation of interest rate risks. Also, a more systematic nationwide collection of property price data, including data on commercial property price developments, would provide a more representative basis for analysis.