<s>
In	O
multivariate	B-General_Concept
statistics	I-General_Concept
,	O
a	O
scree	B-Application
plot	I-Application
is	O
a	O
line	O
plot	O
of	O
the	O
eigenvalues	O
of	O
factors	O
or	O
principal	B-Application
components	I-Application
in	O
an	O
analysis	O
.	O
</s>
<s>
The	O
scree	B-Application
plot	I-Application
is	O
used	O
to	O
determine	O
the	O
number	O
of	O
factors	O
to	O
retain	O
in	O
an	O
exploratory	B-Algorithm
factor	I-Algorithm
analysis	I-Algorithm
(	O
FA	O
)	O
or	O
principal	B-Application
components	I-Application
to	O
keep	O
in	O
a	O
principal	B-Application
component	I-Application
analysis	I-Application
(	O
PCA	O
)	O
.	O
</s>
<s>
The	O
procedure	O
of	O
finding	O
statistically	O
significant	O
factors	O
or	O
components	O
using	O
a	O
scree	B-Application
plot	I-Application
is	O
also	O
known	O
as	O
a	O
scree	B-Application
test	I-Application
.	O
</s>
<s>
Raymond	O
B	O
.	O
Cattell	O
introduced	O
the	O
scree	B-Application
plot	I-Application
in	O
1966	O
.	O
</s>
<s>
A	O
scree	B-Application
plot	I-Application
always	O
displays	O
the	O
eigenvalues	O
in	O
a	O
downward	O
curve	O
,	O
ordering	O
the	O
eigenvalues	O
from	O
largest	O
to	O
smallest	O
.	O
</s>
<s>
According	O
to	O
the	O
scree	B-Application
test	I-Application
,	O
the	O
"	O
elbow	O
"	O
of	O
the	O
graph	O
where	O
the	O
eigenvalues	O
seem	O
to	O
level	O
off	O
is	O
found	O
and	O
factors	O
or	O
components	O
to	O
the	O
left	O
of	O
this	O
point	O
should	O
be	O
retained	O
as	O
significant	O
.	O
</s>
<s>
The	O
scree	B-Application
plot	I-Application
is	O
named	O
after	O
the	O
elbow	O
's	O
resemblance	O
to	O
a	O
scree	O
in	O
nature	O
.	O
</s>
<s>
Scree	B-Application
plots	I-Application
can	O
have	O
multiple	O
"	O
elbows	O
"	O
that	O
make	O
it	O
difficult	O
to	O
know	O
the	O
correct	O
number	O
of	O
factors	O
or	O
components	O
to	O
retain	O
,	O
making	O
the	O
test	O
unreliable	O
.	O
</s>
