AMICO Editorial Committee

Proposal for Indexing Dates

Feburary 18, 1999

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AMICO Date Indexing
Creation Date Text	Indexing Rule	Start Date	End Date	Qualifier
OCT		OCS	OCE	OCQ
Direct translation of entered values
Feb.10, 1874; 2/10/1874		18740210	18740210
AD; A.D.; CE; C.E.				A.D.
BC; B.C.; B.C.E; BCE;				B.C.
YYYY-XXXX or YYYY/XXXX or YYYY to XXXX		YYYY	XXXX
1st century; first century; 1st c.; first cent.;		00010101	00991231	A.D.
12th Century BC, or -12th Century		-1199	-1100	B.C.
c.; c,; ca.; circa; ?; approx.;				circa
Interpreting circa
c.1800 (e.g., c. a century, c.any YY00)	+/- 20 years	17800101	18201231
c.1810 (e.g. c. a decade; c.any YYY0)	+/- 10 years	18000101	18201231
c.1813 (e.g., c. a non-zero ending, year)	+/- 2 years	18110101	18151231
Interpreting partial century expressions
first half of the	years 0-49
second half of the	years 50-99
early; first third of the	years 0-33
mid; second third of the	years 34-66
late; last third of the	years 67-99
Interpreting 'after' and 'before'
after YY00 (e.g.;after 1800)	+20 years	1800	1820
before YY00 (e.g. Before 1800)	-20 years	1870	1800
after YYY0 (e.g. After 1810)	+10 years	1810	1820
before YYY0 (e.g. Before 1810)	-10 years	1800	1810
after YYYY (e.g. After 1813)	+2 years	1813	1815
before YYYY (eg. Before 1813)	-2 years	1811	1813
Dates indexed, but considered ambiguous - WARNINGS message returned
YYYY and XXXX	only first date	YYYY	YYYY
YYYY or XXXX	only first date	YYYY	YYYY
YY	first century	00YY	00YY
YYY	first millenium	0YYY	0YYY
Dates not indexed - ERROR message returned
YYYY-XXXX when XXXX is before YYYY
YYYYMMDD when MM or DD are not possible

Last modified on  February 7, 2002