<s>
In	O
statistics	O
,	O
Goodman	B-General_Concept
and	I-General_Concept
Kruskal	I-General_Concept
's	I-General_Concept
gamma	I-General_Concept
is	O
a	O
measure	O
of	O
rank	O
correlation	O
,	O
i.e.	O
,	O
the	O
similarity	O
of	O
the	O
orderings	O
of	O
the	O
data	O
when	O
ranked	O
by	O
each	O
of	O
the	O
quantities	O
.	O
</s>
<s>
It	O
measures	O
the	O
strength	O
of	O
association	O
of	O
the	O
cross	B-Application
tabulated	I-Application
data	O
when	O
both	O
variables	O
are	O
measured	O
at	O
the	O
ordinal	O
level	O
.	O
</s>
<s>
This	O
statistic	O
(	O
which	O
is	O
distinct	O
from	O
Goodman	B-General_Concept
and	I-General_Concept
Kruskal	I-General_Concept
's	I-General_Concept
lambda	I-General_Concept
)	O
is	O
named	O
after	O
Leo	O
Goodman	O
and	O
William	O
Kruskal	O
,	O
who	O
proposed	O
it	O
in	O
a	O
series	O
of	O
papers	O
from	O
1954	O
to	O
1972	O
.	O
</s>
<s>
Ns	O
,	O
the	O
number	O
of	O
pairs	O
of	O
cases	O
ranked	O
in	O
the	O
same	O
order	O
on	O
both	O
variables	O
(	O
number	O
of	O
concordant	B-General_Concept
pairs	I-General_Concept
)	O
,	O
</s>
<s>
A	O
special	O
case	O
of	O
Goodman	B-General_Concept
and	I-General_Concept
Kruskal	I-General_Concept
's	I-General_Concept
gamma	I-General_Concept
is	O
Yule	O
's	O
Q	O
,	O
also	O
known	O
as	O
the	O
Yule	O
coefficient	O
of	O
association	O
,	O
which	O
is	O
specific	O
to	O
2×2	O
matrices	O
.	O
</s>
<s>
Consider	O
the	O
following	O
contingency	B-Application
table	I-Application
of	O
events	O
,	O
where	O
each	O
value	O
is	O
a	O
count	O
of	O
an	O
event	O
's	O
frequency	O
:	O
</s>
<s>
Although	O
computed	O
in	O
the	O
same	O
fashion	O
as	O
Goodman	B-General_Concept
and	I-General_Concept
Kruskal	I-General_Concept
's	I-General_Concept
gamma	I-General_Concept
,	O
it	O
has	O
a	O
slightly	O
broader	O
interpretation	O
because	O
the	O
distinction	O
between	O
nominal	O
and	O
ordinal	O
scales	O
becomes	O
a	O
matter	O
of	O
arbitrary	O
labeling	O
for	O
dichotomous	O
distinctions	O
.	O
</s>
