C I N T R A F O R
Working Paper 95
Discrepancies in Forest
Products Trade Statistics
John Perez-Garcia
October 2004
This report describes the extent to which discrepancies in trade statistics occur within the forest products sector and identify those areas where unusually large trade statistics discrepancies appear to exist. It also identifies those factors that contribute to discrepancies in the trade statistics and makes recommendations to help trade analysts evaluate and develop a better understanding of the factors that contribute to trade statistics discrepancies.
The literature recognizes a large number of factors that can contribute to
discrepancies in trade statistics between two countries, many of which have
been discussed in this section. However, there is no research available that
describes the relative importance of specific factors in impacting discrepancies
in the trade statistics. From the review of the literature it would seem likely
that this shortcoming is due to the fact that the mix of factors that influence
the unique trade relationship between any two countries tends to be unique
to that trading relationship and that this mix of factors differs substantially
from other combinations of trading partners. In response to this weakness
of the literature, we have provided a relative ranking of trade factors that
impact discrepancies in the trade data by assigning each trade factor to one
of three groups of factors: (a) primary normal factors, (b) secondary normal
factors, and (c) abnormal factors. This ranking of factors was based on the
review of the literature and was done for the sole purpose of providing the
trade analysts involved in the in-depth country studies that follow this study
with guidance in identifying and evaluating the relative impact of specific
trade factors on discrepancies in trade statistics.
The analysis of the trade data demonstrates several fundamental characteristics
of the trade statistics for forest products. First, the average discrepancy
in the trade statistics is greater than zero and the discrepancy ratio becomes
smaller as the degree of processing increases (the difference in discrepancy
ratio was significant between logs and lumber and logs and plywood but not
between lumber and plywood). Second, the majority of the discrepancy ratios
observed for logs, lumber and plywood tended to be positive and concentrated
above the mean discrepancy ratio, indicating that in most cases the magnitude
of the reported imports exceeded that of the reported exports. Third, the
statistical analysis found that, while there was a significant difference
between the size of the trade statistics discrepancy ratios between developed
and less-developed countries across all three products combined, further analysis
determined that, on a specific product basis, this difference was only significant
in the case of lumber. Finally, the trade statistics were statistically analyzed
to establish a "normal" range of trade statistics discrepancies
that might serve as a guide for trade analysts looking to identify unusual
discrepancies that might require further investigation.
This research clearly shows that discrepancies within the trade statistics
are to be expected and anticipated within limits. However, the analysis of
the trade data and the bi-lateral trade statistics discrepancy ratios suggests
that there are substantial discrepancies in the trade statistics for logs,
lumber, and plywood. While there are a variety of reason why we would expect
that reported exports would not equal reported imports, the magnitude of many
of the bi-lateral trade statistics discrepancy ratios observed appear to defy
conventional explanations. Clearly a more in-depth analysis of these problematic
trade flows should to be conducted to determine their causes and, in the process,
begin to develop recommendations to reduce these trade statistics discrepancies
in the future. Finally, despite the difficulties associate with reconciling
trade volumes (based on differences in the types of measurement systems used
in different countries and the lack of timely data), we strongly recommend
that any trade statistics discrepancy analysis consider both the value of
trade and volume of trade.
Finally, this report provides a list of trade factors that could be used to
guide an analysis of trade statistics discrepancies (refer to the following
table). These trade factors have been broken down into: (a) primary normal
factors, (b) secondary normal factors, and (c) abnormal factors based on the
review of the relevant trade literature. It is recommended that an analysis
of trade statistics discrepancies begin by considering the ability of the
primary normal factors to explain the discrepancies in the trade statistics,
and if necessary, the analysis would then consider the role of secondary normal
factors followed by the role of the abnormal factors in contributing to the
trade statistics discrepancy under consideration. Finally, each individual
trade factor listed below is followed by a specific set of recommendations
designed to assist the trade analyst in understanding how each factor might
impact trade statistics discrepancies.
It should be noted that as a result of this study, the International Tropical
Timber Organization has performed a series of country level studies. In each
of these studies, trade analysts looked at specific problems associated with
forest products trade for their countries and communicated with counterparts
in trade partner countries to try and resolve some of the issues raised in
this Working Paper. A synthesis report of the 11 national country studies
will be presented at the ITTO Council Session to be held in Yokohama Japan
in December 2004.
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