<s>
In	O
statistics	O
,	O
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
,	O
also	O
known	O
as	O
the	O
coefficient	B-General_Concept
of	I-General_Concept
colligation	I-General_Concept
,	O
is	O
a	O
measure	O
of	O
association	O
between	O
two	O
binary	O
variables	O
.	O
</s>
<s>
The	O
measure	O
was	O
developed	O
by	O
George	O
Udny	O
Yule	O
in	O
1912	O
,	O
and	O
should	O
not	O
be	O
confused	O
with	O
Yule	O
's	O
coefficient	O
for	O
measuring	O
skewness	B-General_Concept
based	O
on	O
quartiles	O
.	O
</s>
<s>
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
is	O
closely	O
related	O
to	O
the	O
odds	O
ratio	O
OR	O
=	O
ad/	O
( bc	O
)	O
as	O
is	O
seen	O
in	O
following	O
formula	O
:	O
</s>
<s>
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
varies	O
from	O
−1	O
to+1	O
.	O
</s>
<s>
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
is	O
also	O
related	O
to	O
the	O
similar	O
Yule	B-General_Concept
's	I-General_Concept
Q	I-General_Concept
,	O
which	O
can	O
also	O
be	O
expressed	O
in	O
terms	O
of	O
the	O
odds	O
ratio	O
.	O
</s>
<s>
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
gives	O
the	O
fraction	O
of	O
perfect	O
association	O
in	O
per	O
unum	O
(	O
multiplied	O
by	O
100	O
it	O
represents	O
this	O
fraction	O
in	O
a	O
more	O
familiar	O
percentage	O
)	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
association	O
in	O
asymmetric	O
tables	O
can	O
be	O
measured	O
by	O
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
,	O
interpreting	O
it	O
in	O
just	O
the	O
same	O
way	O
as	O
with	O
symmetric	O
tables	O
.	O
</s>
<s>
Of	O
course	O
,	O
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
and	O
(	O
a−b	O
)	O
/	O
( a+b	O
)	O
give	O
the	O
same	O
result	O
in	O
crosswise	O
symmetric	O
tables	O
,	O
presenting	O
the	O
association	O
as	O
a	O
fraction	O
in	O
both	O
cases	O
.	O
</s>
<s>
Yule	B-General_Concept
's	I-General_Concept
Y	I-General_Concept
measures	O
association	O
in	O
a	O
substantial	O
,	O
intuitively	O
understandable	O
way	O
and	O
therefore	O
it	O
is	O
the	O
measure	O
of	O
preference	O
to	O
measure	O
association	O
.	O
</s>
