Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04
  • 2024-05

    • Castro and Cavalcanti used annual data over the

    2018-10-30

    Castro and Cavalcanti (1998) used annual data over the p2x7 receptor 1955–1995 to estimate import and export demand equations. They examined total imports and exports functions as well as their disaggregation by principal end-use category (imports) and aggregate factor (exports). This study was part of the external sector module of the IPEA macroeconometric model (Reis et al., 1999) developed by GAMMA (Grupo de Análise e Modelagem Macroeconômica). Therefore, the authors decided to use imports and exports data measured in dollars instead of indexes of quantum since this enabled them to direct compare their predictions with actual trade balance data. Moreover, it was possible to extend sample size using such data. Compared to Portugal (1992), Castro and Cavalcanti (1998) found very different results. The estimates for aggregate imports and capital goods were satisfactory: along with strong evidence of cointegration, the authors obtained plausible coefficients for the long-run vectors and the error correction models. On the other hand, imports of intermediary goods (exclusive oil) did not even cointegrate. Muinhos et al. (2003) developed specifications of total imports and exports for the Brazilian Central Bank macroeconometric model (structural model with external sector). This paper was the starting point to a more ambitious work, the medium-size macroeconomic model for the Brazilian economy (Muinhos and Alves, 2003). In spite of that, the authors decided to use quarterly indexes of quantum over the period 1988–2001. The empirical exercise did not fully explore the short-run dynamics as the authors chose to work with a partial adjustment equation. Outliers and structural breaks were incorporated into the models using impulse and level dummy variables. The estimated coefficients suggest that the major influence on the quarterly dynamics of imports is the domestic income (impact elasticity of 1.2 and long-run multiplier of 2.7), since the exchange rate coefficients imply an impact elasticity of −0.2 and a long-run multiplier of -0.4. To our knowledge, Ferreira (1994) is the first paper to delve deep into the investigation of structural breaks. The estimations were performed using quarterly data of total imports (quantum index) from 1973 to 1989. A partial adjustment mechanism was introduced into the estimated regression. Stability tests suggested a structural break in 1981. The estimated coefficients for the structural break model indicated a rise in the price elasticity and a reduction in the income elasticity of imports during the 1980s. Table 1 summarizes the point estimates for total import in the studies reviewed so far. It is clear that there is a great variability among these estimates. The studies are different in many respects, such as the data set used, the empirical model and the econometric technique, among others. In the presence of many confounding factors, it turns out to be difficult to find a definitive reason for the differences in the main parameter estimates. Nonetheless, there is an indication that different samples are the preeminent factor behind such discrepancies. In fact, the comparison among different studies, as well as for different periods in the same paper, indicates that the income elasticity of imports was higher in the 1990s than in other decades. Resende (2001) argued that, due to imperfect financial markets, imports were restricted in many periods by the level of international reserves. The author, then, defended the inclusion of a proxy for the capacity to import in estimations of the Brazilian import demand function. Resende applied cointegration and error correction models to estimate total imports and end-use category import equations using quarterly indexes of quantum from 1978 to 1998. Stability tests and structural break regressions were also performed. The results suggest that omitted variable bias occurs when the proxy for capacity to import is not included in models that cover periods before the Real plan. Moreover, the estimations indicate an increase in the income elasticity of imports during the 1990s.