<s>
The	O
main	O
strategies	O
are	O
big	B-Application
bang	I-Application
adoption	I-Application
,	O
parallel	B-Application
adoption	I-Application
and	O
phased	B-Application
adoption	I-Application
.	O
</s>
<s>
"	O
Big	B-Application
bang	I-Application
"	O
is	O
a	O
metaphor	O
for	O
the	B-Application
cosmological	I-Application
theory	I-Application
of	I-Application
the	I-Application
same	I-Application
name	I-Application
,	O
in	O
which	O
the	O
start	O
of	O
the	O
cosmos	O
happened	O
at	O
one	O
moment	O
in	O
time	O
.	O
</s>
<s>
This	O
is	O
also	O
the	O
case	O
with	O
the	O
big	B-Application
bang	I-Application
adoption	I-Application
approach	O
,	O
in	O
which	O
the	O
new	O
system	O
is	O
supposed	O
to	O
be	O
adopted	O
wholesale	O
on	O
one	O
date	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
parallel	B-Application
adoption	I-Application
,	O
the	O
old	O
and	O
the	O
new	O
system	O
are	O
run	O
in	O
parallel	O
initially	O
,	O
so	O
that	O
all	O
the	O
users	O
can	O
get	O
used	O
to	O
the	O
new	O
system	O
,	O
but	O
still	O
can	O
do	O
their	O
work	O
using	O
the	O
old	O
system	O
if	O
they	O
want	O
to	O
or	O
need	O
to	O
do	O
so	O
.	O
</s>
<s>
Phased	B-Application
adoption	I-Application
means	O
that	O
the	O
adoption	O
happens	O
in	O
several	O
phases	O
,	O
so	O
that	O
after	O
each	O
phase	O
the	O
system	O
is	O
a	O
little	O
closer	O
to	O
being	O
fully	O
adopted	O
by	O
the	O
organization	O
.	O
</s>
<s>
The	O
three	O
types	O
of	O
adoption	O
,	O
Big	B-Application
Bang	I-Application
,	O
parallel	B-Application
adoption	I-Application
and	O
phased	B-Application
adoption	I-Application
,	O
range	O
from	O
an	O
instant	O
switch	O
to	O
a	O
strategy	O
where	O
users	O
progressively	O
start	O
using	O
the	O
new	O
system	O
over	O
a	O
certain	O
period	O
of	O
time	O
(	O
which	O
can	O
be	O
weeks	O
,	O
months	O
or	O
even	O
years	O
)	O
.	O
</s>
<s>
due	O
to	O
network	O
effects	O
)	O
,	O
a	O
big	B-Application
bang	I-Application
strategy	O
might	O
be	O
the	O
answer	O
.	O
</s>
