Keun-Yeob Oh

Purchasing power parity and unit root tests using panel data

Abstract This paper reports the results of unit root tests for real exchange rates using a panel framework. This panel approach provides greatly improved power compared to conventional univariate time series unit root tests. We obtain evidence supporting PPP over the recent flexible exchange rate period for G-6 and OECD countries. We show explicitly that failure to find such evidence in previous research was due to the low power of the tests.

Savings-investment cointegration in panel data

Existing cointegration tests for the savings-investment model are limited because of low testing power. In this paper the savings-investment correlation is re-examined using a panel cointegration test by which the power seems to be improved greatly. A cointegration relationship is obtained between the two variables with panel data, and the savings retention coefficient is far from zero. This seems to be consistent with results based on traditional regression methods. Thus, it is concluded that cointegration techniques do not provide the solution to the savings-investment puzzle.

EFFECTS OF PATENTS ON PRODUCTIVITY GROWTH IN KOREAN MANUFACTURING: A PANEL DATA ANALYSIS*

We analyse the contributions of patents to total factor productivity (TFP) performance in Korean manufacturing industries during the period 1981-1999. This paper treats potential autocorrelation problems seriously and uses recent panel cointegration approaches to investigate the robustness of the patent-TFP relationship. The results show that both domestic and foreign-resident patent applications have significant positive effects on productivity and that foreign-resident patent applications have a larger effect than domestic patents in improving TFP in Korean manufacturing. We also find evidence of knowledge spillovers among industries, in that the patent applications of other industries increase TFP in any single industry.

Country size, income level and intra-industry trade

This study investigates three testable hypotheses of intra-industry trade., It begins by developing a theoretical, two country model., The model explicitly includes two goods: differentiated products and homogeneous goods., Then three empirical hypotheses are derived as follows., The share of intra-industry trade will be large: (a) if the two economies are of similar size, (b) if the capital-labour endowment ratio of both countries is similar, and (c) if the total size of the two economies is large., From the cross-sectional analysis using 1970–1994 data, results are obtained that support the model., Furthermore, the results are confirmed using panel analysis on the pooled data.,

An empirical study of the relation between stock price and EPS in panel data: Korea case

This study investigates the relationship between stock price and earnings-per-share using Korean stock market data. The nonstationarity of the data has been managed. In particular, recently developed panel cointegration techniques are used, which are known to be more powerful than individual cointegration methods. The tests applied to the panel data as a whole showed the cointegration relationship between the stock prices and EPS (earnings-per-share), while tests for the individual stock prices could not detect the cointegration. Therefore, there is now some evidence in support of weak mean-reversion for the PER (Price-Earnings Ratio). However, only mixed evidence was obtained for the hypothesis that the coefficient of EPS to the stock prices is equal to one. In short, stock prices do seem to move with firm fundamentals, in the long-run and on average, but not necessarily at the same rate.

Test Of The Convergence Hypothesis Allowing For Cross‐Sectional Dependence

A large empirical literature has investigated whether per capita output converges around a common trend across national and regional economies. The methods used in this literature assume no cross‐sectional dependence even though it is likely to be present and might be important in practice. Chang has devised a promising method of testing for unit roots in heterogeneous panels with cross‐sectional dependence. We apply her method to test whether convergence takes place across three samples of economies: 15 advanced industrial countries; a broader group of 57 countries; and the 48 contiguous US states. We find evidence of convergence for the 15 advanced industrial economies but no evidence of convergence across either the broad group of countries or the US states.

Measuring the welfare effects of intellectual property rights changes on the Korean pharmaceutical industry: the case of Korea–US Free Trade Agreement

This paper shows how to measure the welfare effects of intellectual property rights (IPR) changes under the Korea–US Free Trade Agreement (FTA) on the Korean economy. After the FTA, patent lifetimes are expected to be extended. During such extension periods, Korean generic drug makers will not be able to sell their drugs, and consumers will have to pay more because of higher prices. The new concepts of effective patent term and price-change mechanism were employed, and patent data for the Korean pharmaceutical industry were used to estimate the parameters needed to measure the welfare effects. The empirical results indicate that the welfare effect will be much smaller than suggested by previous studies. These methods to evaluate the welfare effects can be applied to the cases of other recent FTAs and other kinds of IPR negotiations in international economics.