<s>
In	O
the	O
design	O
of	O
experiments	O
,	O
a	O
between-group	B-General_Concept
design	I-General_Concept
is	O
an	O
experiment	O
that	O
has	O
two	O
or	O
more	O
groups	O
of	O
subjects	O
each	O
being	O
tested	O
by	O
a	O
different	O
testing	O
factor	O
simultaneously	O
.	O
</s>
<s>
The	O
simplest	O
between-group	B-General_Concept
design	I-General_Concept
occurs	O
with	O
two	O
groups	O
;	O
one	O
is	O
generally	O
regarded	O
as	O
the	O
treatment	O
group	O
,	O
which	O
receives	O
the	O
‘	O
special’	O
treatment	O
,	O
(	O
that	O
is	O
,	O
is	O
treated	O
with	O
some	O
variable	O
)	O
and	O
the	O
control	O
group	O
,	O
which	O
receives	O
no	O
variable	O
treatment	O
and	O
is	O
used	O
as	O
a	O
reference	O
(	O
prove	O
that	O
any	O
deviation	O
in	O
results	O
from	O
the	O
treatment	O
group	O
is	O
,	O
indeed	O
,	O
a	O
direct	O
result	O
of	O
the	O
variable	O
.	O
)	O
</s>
<s>
The	O
between-group	B-General_Concept
design	I-General_Concept
is	O
widely	O
used	O
in	O
psychological	O
,	O
economic	O
,	O
and	O
sociological	O
experiments	O
,	O
as	O
well	O
as	O
in	O
several	O
other	O
fields	O
in	O
the	O
natural	O
or	O
social	O
sciences	O
.	O
</s>
<s>
In	O
order	O
to	O
avoid	O
experimental	O
bias	O
,	O
experimental	O
blinds	O
are	O
usually	O
applied	O
in	O
between-group	B-General_Concept
designs	I-General_Concept
.	O
</s>
<s>
The	O
main	O
disadvantage	O
with	O
between-group	B-General_Concept
designs	I-General_Concept
is	O
that	O
they	O
can	O
be	O
complex	O
and	O
often	O
require	O
a	O
large	O
number	O
of	O
participants	O
to	O
generate	O
any	O
useful	O
and	O
reliable	O
data	O
.	O
</s>
<s>
The	O
potential	O
scale	O
of	O
these	O
experiments	O
can	O
make	O
between-group	B-General_Concept
designs	I-General_Concept
impractical	O
due	O
to	O
limited	O
resources	O
,	O
subjects	O
and	O
space	O
.	O
</s>
<s>
Another	O
major	O
concern	O
for	O
between-group	B-General_Concept
designs	I-General_Concept
is	O
bias	O
.	O
</s>
<s>
Assignment	O
bias	O
,	O
observer-expectancy	O
and	O
subject-expectancy	O
biases	O
are	O
common	O
causes	O
for	O
skewed	B-General_Concept
data	I-General_Concept
results	O
in	O
between-group	O
experiments	O
,	O
which	O
can	O
lead	O
to	O
false	O
conclusions	O
being	O
drawn	O
.	O
</s>
<s>
Some	O
other	O
disadvantages	O
for	O
between-group	B-General_Concept
designs	I-General_Concept
are	O
generalization	O
,	O
individual	O
variability	O
and	O
environmental	O
factors	O
.	O
</s>
<s>
Some	O
research	O
has	O
been	O
done	O
regarding	O
whether	O
it	O
is	O
possible	O
to	O
design	O
an	O
experiment	O
that	O
combines	O
within-subject	O
design	O
and	O
between-group	B-General_Concept
design	I-General_Concept
,	O
or	O
if	O
they	O
are	O
distinct	O
methods	O
.	O
</s>
