سرمایه گذاری موجودی و ویژگی های تولید ناخالص ملی در کشورهای سازمان همکاری و توسعه

There are very few research studies on macroeconomic inventory behaviour of various countries. It is clear that macro inventories are the results of a large number of individual microdecisions. However, we believe that it is worth analysing how inventories develop in the individual countries and why we can see different tendencies. This paper is the newest piece in a series of studies on the above subject. We use the OECD database to analyse inventory trends between 1987 and 2004 in nine of the most developed economies of the world. Annual inventory investment data are used and their connections with other components of GDP expenditure (governmental and private consumption, investment in fixed assets and foreign trade balance as well as the annual growth rate of GDP) are examined by multi-variable statistical analysis. Conclusions include the steadily decreasing tendency of inventory fluctuations, the varying periods of higher and lower rates of inventory investments and the differences of main influencing factors by country.

This paper is a continuation of a series of studies that are aimed to disclose connections between inventory investment and other macroeconomic indicators, as well as to explain their tendencies and countrywise differences. We believe that it makes sense to ask: what are the driving forces and consequences of different inventory behaviour of various economies? Some interesting conclusions could already be drawn (for a summary of previous results and consequences, see Chikán and Tátrai, 2003; Chikán et al., 2005). For the current study, we have again used the OECD database (www.oecd.org) and applied SPSS (1994). We have found all necessary data from 10 countries: Belgium Canada Finland France Italy Japan The Netherlands Sweden United Kingdom United States This list of countries is shorter than in our previous study—the database does not contain appropriate inventory data from Denmark, Germany, Ireland and Spain. Also, Italy has been left out since there were unexplainably high inventory investment data in the database, which could not be considered other than some statistical mistake. Just like in previous studies, we have used annual data because of lack of a more detailed database. Again, we emphasize that since our objective is to discuss long-term characteristics, annual data are sufficient. It is also our obligation to call attention to the uncertainty involved in any macroeconomic data analysis—because of that we must be very careful in the interpretation of results. It should also be added that our results published in Chikán et al. (2005) cannot be directly compared with those in this paper since in the previous study OECD data were given in 1990 USD, while in the meantime data came out in 2000 USD. We believe that even though a direct comparison would have been interesting, our main results are not influenced by that change. In Chikán et al. (2005) we used USD 1990 data from 1968 to 1997 (30 years) divided into two subperiods: 1968–1983 and 1984–1997. Now we have a homogeneous data set of USD 2000 data between 1987 and 2004 (18 years). The 11-year overlap between the two data sets establishes a sound connection between the two time series.

The analysis has given us very interesting insights regarding the long-term characteristics of macroeconomic inventory behaviour of various countries. These results have at some points reinforced results of our previous studies, but at some other points they put question marks to previously disclosed trends. The most important result probably is that inventory fluctuations in the developed countries are steadily decreasing, and the data are closer and closer to each other. This suggests that some kind of a “normal” inventory investment can be observed. A second important conclusion is that even though the variation of inventory investment is decreasing, the underlying causes of this tendency are very different by countries and by time periods. No general model can be found which would describe the connection between inventory investment and other components of the GDP. It is also an interesting finding that the main influencing factor of STOCK is the growth rate of GDP—this leads to important conclusions regarding economic policy in a period of fast growth. The third major result is that inventory investment seems to grow again in the last few years. In the turn of the 1990s we found that no evidence suggests a decreasing tendency of inventories (Chikán et al., 1996). Later we found that the trend is decreasing (Chikán and Tátrai, 2003)—and now there is a period of increase again. Even though this increase is only at a small scale, its appearance is enough to show: we do not have any explanation yet to many inventory phenomena.