WESTAT
An
Employee­
Owned
Research
Corporation
MEMORANDUM
cc:
Kurt
Patrizi,
Westat
TO:
John
Fox,
EPA
October
07,
2003
FROM:
G.
Hussain
Choudhry
and
Inho
Park
Project
No.
:
7273­
03
COPY
TO:
George
Denning
(
EPA),
Carey
Johnston
(
EPA)
and
Anne
Jones
(
ERG).
Memo
No.
:
4­
90
SUBJECT:
Sampling
Selection
for
Offshore
Oil
&
Gas
­
TD
#
W040917a
dated
September
17,
2003.

This
memo
and
the
attached
excel
files
constitute
the
deliverable
specified
in
the
TD
#
W040917a
dated
September
17,
2003.
Westat
was
asked
to
complete
a
sampling
design
and
provide
a
sample
of
Oil
&
Gas
facilities.
The
sampling
frames
provide
the
lists
of
facilities
for
the
following
sub­
populations:

 
Deep
Water,

 
More
than
20
Slots,

 
California,

 
Alaska,

 
Shallow
Waters,
and
 
MODUs.

The
frames
contained
both
in­
scope
and
out­
of­
scope
facilities
and
we
deleted
the
out­
of­
scope
facilities
from
the
frames.
The
facilities
for
which
eligibility
was
unknown
were
retained
in
the
sampling
frame.
The
number
of
facilities
in
each
sub­
population
and
the
number
sampled
are
given
in
Table
1.

Table
1:
Number
of
In­
Scope
Facilities
and
Number
Sampled
by
Frame.

Survey
IDs
FRAME
Number
of
Facilities
From
To
Number
of
Facilities
Sampled
Deep
Water
24
WS100001
WS100024
4
More
than
20
Slots
206
WS200001
WS200206
33
California
20
WS300001
WS300020
3
Alaska
19
WS400001
WS400019
2
Shallow
Waters
2,194
WS500001
WS502194
18
MODUs
404
WS600001
WS600404
30
All
Frames
2,867
­­
­­
90
Memorandum
4­
90
September
07,
2003
2
The
frames
were
sorted
by
company
name
and
systematic
sample
of
facilities
was
selected
independently
from
each
of
the
frames.
We
also
assigned
unique
survey
IDs
to
the
facilities.
The
variable
SURVEYID
gives
the
unique
survey
ID
for
each
facility,
and
the
sampling
flag
(
SAMPFLG)

identifies
the
sampled
facilities.

SAMPFLG
=
1
if
facility
is
sampled,

=
0,
otherwise.

The
range
of
unique
survey
IDs
for
each
of
the
frames
is
given
in
Table
1
above.

Delivery
of
Files
The
attached
excel
files
"
ws1_
deepwater",
"
ws2_
20+
slots",
""
ws3_
CA",
"
ws4_
Alaska",

"
ws5_
shallow­
waters"
and
"
ws6_
MODUs"
provide
the
sampling
flag
(
SAMPFLG)
and
survey
IDs
(
SURVEYID)
for
the
six
frames.
