D5 Annex report WP 3: ETIS Database methodology ... - ETIS plus

D5 Annex WP 3: DATABASE METHODOLOGY AND DATABASE USER MANUAL –
FREIGHT TRANSPORT DEMAND
Year 2000: Trade Volumes, Tonnes, SITC 89, Miscellaneous Manufactures
F NL D IT UK IRL DK EL PT Total
F 816,186
NL 667,127
D 1,403,972
IT 960,777
UK 519,952
IRL 141,677
DK 125,798
EL 22,545
PT 68,102
Total 1,149,272 406,307 939,382 304,014 986,052 158,838 183,114 500,563 98,594 4,726,136
In fact, all the cells in this table are known, but if region to region totals rather than country to
country totals are sought, a method has to be found to complete the matrix. Therefore the test
has been carried out at the higher level so that different estimation methods can be compared
against known values.
For reference, the actual matrix is:
Year 2000: Trade Volumes, Tonnes, SITC 89, Miscellaneous Manufactures: Actuals
F NL D IT UK IRL DK EL PT Total
F 42,646 305,370 81,523 212,456 5,734 8,779 127,529 32,149 816,186
NL 157,066 229,456 37,627 159,176 7,616 31,419 31,298 13,469 667,127
D 444,615 245,475 129,615 363,540 17,501 106,381 71,863 24,982 1,403,972
IT 359,208 37,894 193,248 130,637 5,911 14,713 202,331 16,835 960,777
UK 121,061 56,900 92,344 37,424 120,762 18,461 63,197 9,803 519,952
IRL 28,327 4,066 14,550 4,876 85,103 1,975 2,411 369 141,677
DK 19,991 13,039 59,594 4,789 25,413 956 1,060 956 125,798
EL 3,704 5,669 4,618 5,413 2,569 182 359 31 22,545
PT 15,300 618 40,202 2,747 7,158 176 1,027 874 68,102
Total 1,149,272 406,307 939,382 304,014 986,052 158,838 183,114 500,563 98,594 4,726,136
The first possibility is to fill in the matrix using a purely mechanical Furness algorithm, which
attempts to find a solution (out of many feasible solutions) without the need for any underlying
model. It works by seeding the initial matrix with zeroes on the leading diagonal, and ones
elsewhere, and then successively factoring up the rows and then the columns so that the sums in
the rows and columns tend toward the known row and column totals. After a few cycles, the
algorithm “succeeds”.
A Solution by Furnessing at the 2 Digit Level
F NL D IT UK IRL DK EL PT Total
F 0 88,519 264,571 70,492 211,403 30,995 35,631 95,597 18,978 816,186
NL 180,483 0 176,938 47,143 141,380 20,729 23,829 63,933 12,692 667,127
D 461,227 151,284 0 120,475 361,300 52,972 60,896 163,382 32,435 1,403,972
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Document2
27 May 2004