<s>
In	O
human	O
computer	O
interaction	O
,	O
the	O
gulf	B-General_Concept
of	I-General_Concept
execution	I-General_Concept
is	O
the	O
gap	O
between	O
a	O
user	O
's	O
goal	O
for	O
action	O
and	O
the	O
means	O
to	O
execute	O
that	O
goal	O
.	O
</s>
<s>
Usability	B-General_Concept
has	O
as	O
one	O
of	O
its	O
primary	O
goals	O
to	O
reduce	O
this	O
gap	O
by	O
removing	O
roadblocks	O
and	O
steps	O
that	O
cause	O
extra	O
thinking	O
and	O
actions	O
that	O
distract	O
the	O
user	O
's	O
attention	O
from	O
the	O
task	O
intended	O
,	O
thereby	O
preventing	O
the	O
flow	O
of	O
his	O
or	O
her	O
work	O
,	O
and	O
decreasing	O
the	O
chance	O
of	O
successful	O
completion	O
of	O
the	O
task	O
.	O
</s>
<s>
Similarly	O
,	O
there	O
is	O
a	O
gulf	B-General_Concept
of	I-General_Concept
evaluation	I-General_Concept
that	O
applies	O
to	O
the	O
gap	O
between	O
an	O
external	O
stimulus	O
and	O
the	O
time	O
a	O
person	O
understands	O
what	O
it	O
means	O
.	O
</s>
<s>
The	O
difference	O
between	O
the	O
user	O
's	O
perceived	O
execution	O
actions	O
and	O
the	O
required	O
actions	O
is	O
the	O
gulf	B-General_Concept
of	I-General_Concept
execution	I-General_Concept
.	O
</s>
