<s>
Construction	O
cost	O
estimating	O
software	O
is	O
computer	B-Application
software	I-Application
designed	O
for	O
contractors	O
to	O
estimate	O
construction	O
costs	O
for	O
a	O
specific	O
project	O
.	O
</s>
<s>
They	O
became	O
known	O
as	O
green	O
sheets	O
or	O
spreadsheets	B-Application
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
computers	O
in	O
business	O
,	O
estimators	O
began	O
using	O
spreadsheet	B-Application
applications	O
like	O
VisiCalc	B-Application
,	O
Lotus	B-Application
1-2-3	I-Application
,	O
and	O
Microsoft	B-Application
Excel	I-Application
to	O
duplicate	O
the	O
traditional	O
tabular	O
format	O
,	O
while	O
automating	O
redundant	O
mathematical	O
formulas	O
.	O
</s>
<s>
Many	O
construction	O
cost	O
estimators	O
continue	O
to	O
rely	O
primarily	O
upon	O
manual	O
methods	O
,	O
hard	O
copy	O
documents	O
,	O
and/or	O
electronic	O
spreadsheets	B-Application
such	O
as	O
Microsoft	B-Application
Excel	I-Application
.	O
</s>
<s>
While	O
spreadsheets	B-Application
are	O
relatively	O
easy	O
to	O
master	O
and	O
provide	O
a	O
means	O
to	O
create	O
and	O
report	O
a	O
construction	O
cost	O
estimate	O
and	O
or	O
cost	O
models	O
,	O
their	O
benefit	O
comes	O
largely	O
from	O
their	O
ability	O
to	O
partially	O
relieve	O
estimators	O
of	O
mundane	O
calculations	O
.	O
</s>
<s>
As	O
cost	O
estimators	O
came	O
to	O
rely	O
heavily	O
on	O
spreadsheets	B-Application
,	O
and	O
the	O
formulas	O
within	O
the	O
spreadsheets	B-Application
became	O
more	O
complex	O
,	O
spreadsheet	B-Application
errors	O
became	O
more	O
frequent	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
commercial	O
cost	O
estimating	O
software	B-Application
applications	I-Application
were	O
originally	O
created	O
to	O
overcome	O
these	O
errors	O
by	O
using	O
hard-coded	O
formulas	O
and	O
data	O
structures	O
.	O
</s>
<s>
Item	O
or	O
Activity	O
List	O
:	O
All	O
estimating	O
software	B-Application
applications	I-Application
will	O
include	O
a	O
main	O
project	O
window	O
that	O
outlines	O
the	O
various	O
items	O
or	O
activities	O
that	O
will	O
be	O
required	O
to	O
complete	O
the	O
specified	O
project	O
.	O
</s>
<s>
Exporting	O
:	O
Most	O
software	O
programs	O
can	O
export	O
project	O
data	O
to	O
other	O
applications	O
,	O
such	O
as	O
spreadsheets	B-Application
,	O
accounting	B-Application
software	I-Application
,	O
and	O
project	B-Application
management	I-Application
software	I-Application
.	O
</s>
