<s>
A	O
forest	B-Application
plot	I-Application
,	O
also	O
known	O
as	O
a	O
blobbogram	B-Application
,	O
is	O
a	O
graphical	O
display	O
of	O
estimated	O
results	O
from	O
a	O
number	O
of	O
scientific	O
studies	O
addressing	O
the	O
same	O
question	O
,	O
along	O
with	O
the	O
overall	O
results	O
.	O
</s>
<s>
environmental	O
epidemiology	O
)	O
and	O
forest	B-Application
plots	I-Application
are	O
often	O
used	O
in	O
presenting	O
the	O
results	O
of	O
such	O
studies	O
also	O
.	O
</s>
<s>
Although	O
forest	B-Application
plots	I-Application
can	O
take	O
several	O
forms	O
,	O
they	O
are	O
commonly	O
presented	O
with	O
two	O
columns	O
.	O
</s>
<s>
Forest	B-Application
plots	I-Application
date	O
back	O
to	O
at	O
least	O
the	O
1970s	O
.	O
</s>
<s>
The	O
first	O
use	O
in	O
print	O
of	O
the	O
expression	O
"	O
forest	B-Application
plot	I-Application
"	O
may	O
be	O
in	O
an	O
abstract	O
for	O
a	O
poster	O
at	O
the	O
Pittsburgh	O
(	O
US	O
)	O
meeting	O
of	O
the	O
Society	O
for	O
Clinical	O
Trials	O
in	O
May	O
1996	O
.	O
</s>
<s>
An	O
informative	O
investigation	O
on	O
the	O
origin	O
of	O
the	O
notion	O
"	O
forest	B-Application
plot	I-Application
"	O
was	O
published	O
in	O
2001	O
.	O
</s>
<s>
In	O
September	O
1990	O
,	O
Richard	O
Peto	O
joked	O
that	O
the	O
plot	O
was	O
named	O
after	O
a	O
breast	O
cancer	O
researcher	O
called	O
Pat	O
Forrest	O
and	O
as	O
a	O
result	O
the	O
name	O
has	O
sometimes	O
been	O
spelled	O
"	O
forrest	B-Application
plot	I-Application
"	O
.	O
</s>
<s>
This	O
blobbogram	B-Application
is	O
from	O
an	O
iconic	O
medical	O
review	O
;	O
it	O
shows	O
clinical	O
trials	O
of	O
the	O
use	O
of	O
corticosteroids	O
to	O
hasten	O
lung	O
development	O
in	O
pregnancies	O
where	O
a	O
baby	O
is	O
likely	O
to	O
be	O
born	O
prematurely	O
.	O
</s>
<s>
Studies	O
included	O
in	O
the	O
meta-analysis	O
and	O
incorporated	O
into	O
the	O
forest	B-Application
plot	I-Application
will	O
generally	O
be	O
identified	O
in	O
chronological	O
order	O
on	O
the	O
left	O
hand	O
side	O
by	O
author	O
and	O
date	O
.	O
</s>
<s>
The	O
chart	O
portion	O
of	O
the	O
forest	B-Application
plot	I-Application
will	O
be	O
on	O
the	O
right	O
hand	O
side	O
and	O
will	O
indicate	O
the	O
mean	O
difference	O
in	O
effect	O
between	O
the	O
test	O
and	O
control	O
groups	O
in	O
the	O
studies	O
.	O
</s>
<s>
If	O
either	O
the	O
box	O
or	O
the	O
confidence	O
interval	O
whiskers	O
pass	O
through	O
the	O
y-axis	O
of	O
no	O
effect	O
,	O
the	O
study	O
data	O
is	O
said	O
to	O
be	O
statistically	B-General_Concept
insignificant	I-General_Concept
.	O
</s>
<s>
The	O
meaningfulness	O
of	O
the	O
study	O
data	O
,	O
or	O
power	B-General_Concept
,	O
is	O
indicated	O
by	O
the	O
weight	O
(	O
size	O
)	O
of	O
the	O
box	O
.	O
</s>
<s>
The	O
forest	B-Application
plot	I-Application
is	O
able	O
to	O
demonstrate	O
the	O
degree	O
to	O
which	O
data	O
from	O
multiple	O
studies	O
observing	O
the	O
same	O
effect	O
overlap	O
with	O
one	O
another	O
.	O
</s>
<s>
Results	O
that	O
fail	O
to	O
overlap	O
well	O
are	O
termed	O
heterogeneous	B-General_Concept
and	O
is	O
referred	O
to	O
as	O
the	O
heterogeneity	B-General_Concept
of	O
the	O
data	O
—	O
such	O
data	O
is	O
less	O
conclusive	O
.	O
</s>
<s>
If	O
the	O
results	O
are	O
similar	O
between	O
various	O
studies	O
,	O
the	O
data	O
is	O
said	O
to	O
be	O
homogeneous	B-General_Concept
,	O
and	O
the	O
tendency	O
is	O
for	O
these	O
data	O
to	O
be	O
more	O
conclusive	O
.	O
</s>
<s>
The	O
heterogeneity	B-General_Concept
is	O
indicated	O
by	O
the	O
I2	O
.	O
</s>
<s>
A	O
heterogeneity	B-General_Concept
of	O
less	O
than	O
50%	O
is	O
termed	O
low	O
,	O
and	O
indicates	O
a	O
greater	O
degree	O
of	O
similarity	O
between	O
study	O
data	O
than	O
an	O
I2	O
value	O
above	O
50%	O
,	O
which	O
indicates	O
more	O
dissimilarity	O
.	O
</s>
