Table 7. Difference matrix showing mean isotopic differences between laboratories for bone hydroxyapatite results; δ¹³C_ap above diagonal, δ¹⁸O_ap beneath diagonal.

Lab			A	B	C	D	F	G	H	I	K	N1	N2	O	P	R	S	T
	δ13Cap-VPDB (‰)		−11.5	−11.6	−12.0	−11.4	−12.4	−12.3	−11.9	−11.7	−11.7	−11.4	−12.2	−11.3	−11.9	−10.1	−12.4	−11.6
		δ18Oap-VPDB (‰)	−2.6	−7.1	−3.1	−2.5	−5.9	−4.5	−4.1	−6.2	−3.4	−3.2	−3.4	−6.7	−3.5	−7.4	−6.2	−2.8
A	−11.5	−2.6	-	0.1	0.5	0.1	0.9	0.9	0.4	0.2	0.2	0.1	0.7	0.2	0.4	1.4	0.9	0.1
B	−11.6	−7.1	4.5	-	0.4	0.2	0.8	0.8	0.3	0.1	0.1	0.2	0.6	0.3	0.3	1.4	0.8	0.0
C	−12.0	−3.1	0.5	4.0	-	0.6	0.4	0.3	0.1	0.3	0.3	0.6	0.2	0.7	0.1	1.9	0.4	0.4
D	−11.4	−2.5	0.1	4.6	0.6	-	1.0	1.0	0.5	0.3	0.3	0.0	0.8	0.1	0.6	1.2	1.0	0.2
F	−12.4	−5.9	3.2	1.2	2.7	3.3	-	0.0	0.4	0.7	0.7	1.0	0.2	1.1	0.4	2.2	0.1	0.8
G	−12.3	−4.5	1.9	2.6	1.4	2.0	1.4	-	0.4	0.7	0.7	1.0	0.2	1.0	0.4	2.2	0.1	0.8
H	−11.9	−4.1	1.4	3.0	1.0	1.6	1.8	0.4	-	0.3	0.2	0.6	0.2	0.6	0.0	1.8	0.5	0.4
I	−11.7	−6.2	3.6	0.9	3.1	3.7	0.4	1.8	2.2	-	0.0	0.3	0.5	0.4	0.3	1.5	0.7	0.1
K	−11.7	−3.4	0.8	3.7	0.3	0.9	2.4	1.0	0.6	2.8	-	0.3	0.5	0.4	0.3	1.5	0.7	0.1
N1	−11.4	−3.2	0.5	4.0	0.0	0.6	2.7	1.3	0.9	3.1	0.3	-	0.8	0.0	0.6	1.2	1.1	0.2
N2	−12.2	−3.4	0.8	3.7	0.3	0.9	2.5	1.1	0.7	2.8	0.0	0.3	-	0.9	0.2	2.0	0.2	0.6
O	−11.3	−6.7	4.0	0.5	3.5	4.1	0.8	2.2	2.6	0.4	3.2	3.5	3.3	-	0.6	1.2	1.1	0.3
P	−11.9	−3.5	0.9	3.6	0.4	1.0	2.3	1.0	0.6	2.7	0.1	0.4	0.1	3.1	-	1.8	0.5	0.4
R	−10.1	−7.4	4.7	0.3	4.2	4.8	1.5	2.9	3.3	1.1	3.9	4.2	4.0	0.7	3.8	-	2.3	1.4
S	−12.4	−6.2	3.6	0.9	3.1	3.7	0.3	1.7	2.1	0.0	2.8	3.1	2.8	0.4	2.7	1.2	-	0.9
T	−11.6	−2.8	0.2	4.3	0.3	0.3	3.0	1.7	1.2	3.4	0.6	0.3	0.6	3.8	0.7	4.5	3.4	-