Ian, this discussion is worthwhile. Thank you! The SEMI
equipment data is reported in a straightforward manner
as 3 months moving average:
Example
Month Shipments Bookings Book-to-Bill
September 99 1,412.9 1,510.7 1.07
October 99 1,484.3 1,609.5 1.08
November 99 1,528.5 1,694.5 1.11
December 99 (final) 1,597.9 1,907.6 1.19
January 2000 (revised) 1,605.4 2,226.3 1.39
February 2000 (prelim.) 1,605.7 2,268.0 1.41
I replace my old December data with the new, which is then frozen because it is final.
semi.org!OpenDocument
The SIA data is not as clear. All data is 3 months moving
averages, but I see no revisions. I think I'll call them
tomorrow for an explanation - unless you can provide one.
semichips.org
Gottfried |
