The calculation of a record comparison weight as the
sum of the weights of the field comparison weights relies on the assumption that the fields being
weighted are independent (cf. ¶ 2-2.5, ¶ 4-1.4). The comparison space might be configured much as
diagramed in figure 1 [NB: Within a field, agreement is still dependent on presence.] This means
that the probability of a comparison being a match would be directly proportional to the calculated
agreement weight of each independent field. Consider the reliability and coincidence for the two
fields in table 3 and see what weight they might contribute to a comparison. When the fields are
independent we allow for the Given Name Code to agree even when the Sex is not the same. But
in reality the Sex may be so reliable that the probability of this happening would be virtually zero.
We say that the Sex depends on the Given Name Code. Another way of saying this is that the Given
Name Code partitions the Sex.
| FIELDPresence | Reliability & Coincidence |
W E I G H T S F O R C O M B I N A T I O N S (+ = agreement – = disagreement 0 = missing) | |||||||||
| p | r | c | + + | + – | + 0 | – + | – – | – 0 | 0 + | 0 – | 0 0 |
| Principal's Given Name Code 0.9679 |
0.9617 | 0.0250 | aw1 = +5.27 |
aw1 = +5.27 |
aw1 = +5.27 |
dw1 = –7.25 |
dw1 = –7.25 |
dw1 = –7.25 |
bw1 = 0.00 |
bw1 = 0.00 |
bw1 = 0.00 |
| Principal's Sex 1.0000 |
0.9932 | 0.5004 | aw2 = +0.99 |
dw2 = –6.20 |
bw2 = 0.00 |
aw2 = +0.99 |
dw2 = –6.20 |
bw2 = 0.00 |
aw2 = +0.99 |
dw2 = –6.20 |
bw2 = 0.00 |
| Algorithm if Independent |  cw = +6.26 |
cw = –0.93 |
cw = +5.27 |
cw = –6.26 |
cw = –13.5 |
cw = –7.25 |
cw = +0.99 |
cw = –6.20 |
cw = 0.00 | ||
