The samples do
not include any mine-mouth plants using
eastern coal, so columns 3 and 7 simply
report the estimated relationship between
DURATION and LOG-QUANTITY. There
are in fact a few mine-mouth plants in the
East and I have some information for three
of them. These were not included in the
sample because the data base did not have
information on annual contract quantities
for them. However, I was able to obtain
information for delivered quantities for three
eastern mine-mouth plants and have augmented the sample to include these plants,
using delivered quantities rather than contract
quantities as the values fort he QUANTITY
variable.These results are reported in
columns 4 and 8 of Table 6.36
The effects of contract quantity and the
mine-mouth dummy on contract duration
are clearly not simply associated with the
contracting behavior for coal from a particular
region.The expected effects are found in
each of the three regions.The coefficients of
QUANTITY and MINE-MOUTH are of the
expected signs and are estimated precisely in
all cases. While there are differences in the
magnitudes of the coefficients of these variables
between the three regions, they are not
very large numerically and equality of the
coefficients of QUANTITY and MINEMOUTH
across regions cannot be rejected
at standard significance levels. Contracts
basically simply get longer as we move from
East to West,othert hingse qual