FILE nes2004panel_app.txt
-------------------------
American National Election Studies: 2004 Panel Study (2004.S)
Codebook appendix file
VERSION 20050502 (May 2, 2005)


>> 2004 PANEL APPENDIX:  2000 NATIONAL ELECTION STUDY SAMPLE DESIGN

STUDY POPULATION

     The study population for the 2000 Pre- and Post-Election Study is defined
to include all United States citizens of voting age on or before the 2000
Election Day.  Eligible citizens must have resided in housing units in the
forty-eight coterminous states.  This definition excludes persons living in
Alaska or Hawaii and requires eligible persons to have been both a United
States citizen and eighteen years of age on or before the 7th of November
2000.

>> DUAL FRAME SAMPLE DESIGN

The 2000 NES is a dual frame sample with both an area sample and an RDD 
component.  The RDD frame provides coverage of telephone households while the 
area sample provides full coverage of all U.S. households including those 
without telephones.  Each of these sample designs will be described in the 
following sections.  The 2000 NES data set contains 1006 area sample cases 
and 801 telephone sample cases.

>> FTF SAMPLE DESIGN - MULTI-STAGE AREA PROBABILITY

The area sample is based on a multi-stage area probability sample selected 
from the Survey Research Center's (SRC) 1990 National Sample design. 
Identification of the 2000 NES sample respondents was conducted using a four 
stage sampling process--a primary stage sampling of U.S. Metropolitan
Statistical Areas (MSAs) or New England County Metropolitan Areas (NECMAs) 
and non-MSA counties, followed by a second stage sampling of area segments, a 
third stage sampling of housing units within sampled area segments and 
concluding with the random selection of a single respondent from selected 
housing units.  A detailed documentation of the 1990 SRC National Sample, 
from which the 2000 NES sample was drawn, is provided in the SRC publication 
titled 1990 SRC National Sample: Design and Development.  

The 2000 NES sample design called for an entirely new cross-section sample to 
be drawn from the 1990 SRC National Sample; no panel component was included 
in 2000.    The 1990 SRC National Sample is a multi-stage area probability 
sample.  The 2000 NES sample was drawn from both the 1990 SRC National Sample 
strata (MSA PSUs) and the 1980 SRC National Sample strata  (non-MSA PSUs). 
The modification of the 1990 design in which the 1980 strata definitions were 
used for the non-MSA counties fully represents the non-MSA domain of the 48 
contiguous states.  This modification was made for cost and interviewing 
efficiency reasons related to the availability of interviewers in these areas 
who work on some of SRC's large panel studies.  The following sections will 
focus on the 1990 SRC National Sample design.


Selection Stages for the 2000 NES FTF Sample: 1990 SRC National Sample
------------------------------------------------------------------

Primary Stage Selection

The selection of primary stage sampling units (PSUs) for the 1990 SRC 
National Sample, which depending on the sample stratum are either MSAs, New 
England County Metropolitan Areas (NECMAs), single counties, independent 
cities, county equivalents or groupings of small counties, is based on the 
county-level 1990 Census Reports of Population and Housing (1).  Primary stage 
units were assigned to 108 explicit strata based on MSA/NECMA or non-
MSA/NECMA status, PSU size, Census Region and geographic location within 
region.  Twenty-eight of the 108 strata contain only a single self-
representing PSU, each of which is included with certainty in the primary 
stage of sample selection.  The remaining 80 nonself-representing strata 
contain more than one PSU.  From each of these nonself-representing strata, 
one PSU was sampled with probability proportionate to its size (PPS) measured 
in 1990 occupied housing units. 

The full 1990 SRC National Sample of 108 primary stage selections was 
designed to be optimal for surveys roughly three to five times the size of 
the 2000 NES.  To permit the flexibility needed for optimal design of smaller 
survey samples, the primary stage of the SRC National Sample can be readily 
partitioned into smaller subsamples of PSUs such as a one-half sample or a 
three-quarter sample partition.  Each of the partitions represents a 
stratified subselection from the full 108 PSU design.  The 2000 NES sample of 
44 PSUs is a stratified random subsample of PSUs from the "A" half-sample 
partition of the 1990 SRC National Sample.  Because of the small size of this 
NES sample, both the number of PSUs (selected primary areas) and the 
secondary stage units (area segments) in the National half-sample were 
reduced by subselection for the 2000 NES sample design.  The 18 self-
representing areas in the 1990 SRC National half-sample were all retained for 
the 2000 NES sample (8 of these remained self-representing in the 2000 NES 
and 10 represent not only their own MSA but their "pair" among the twenty 
additional self-representing primary areas of the full 1990 SRC National 
Sample design).  Nineteen of the 26 nonself-representing half-sample MSAs and 
7 of the 14 half-sample non-MSAs were retained by the subselection for the 
2000 NES sample (or 26 of 40 NSR PSUs).

(1)  Office of Management and Budget (OMB) June 1990 definitions of MSAs,
NECMAs, counties, parishes, independent cities.  These, of course, differ in
some respects from the primary stage unit (PSU) definitions used in the 1980
SRC National Sample so will not be strictly comparable to the 1996 NES Panel
PSUs--particularly in New England where MSAs were used as PSUs in the 1980
National Sample and NECMAs were used as PSUs in the 1990 National Sample.

Second Stage Selection Area Segments

The second stage of the 1990 SRC National Sample, used for the 2000 NES 
sample, was selected directly from computerized files that were extracted for 
the selected PSUs from the 1990 U.S. Census summary file series STF1-B.  
These files (on CD Rom) contain the 1990 Census total population and housing 
unit (HU) data at the census block level.  The designated second-stage 
sampling units (SSUs), termed "area segments", are comprised of census blocks 
in both the metropolitan (MSA) primary areas and in the rural areas of non-
MSA primary areas.  Each SSU block or block combination was assigned a 
measure of size equal to the total 1990 occupied housing unit count for the 
area.  SSU block(s) were assigned a minimum measure of 72 1990 total HUs per 
MSA SSU and a minimum measure of 48 total HUs per non-MSA SSU.  Second stage 
sampling of area segments was performed with probabilities proportionate to 
the assigned measures of size (PPS).  

For the 2000 NES sample the number of area segments used in each PSU varies. 
In the self-representing (SR) PSUs the number of area segments varies in 
proportion to the size of the primary stage unit, from a high of 12 area 
segments in the self-representing New York and Los Angeles MSA PSUs, to a low 
of 6 area segments in the smaller self-representing PSUs such as Cleveland, 
Miami-Hialeah or Nassau-Suffolk MSAs.  All nonself-representing (NSR) PSUs 
were represented by 6 area segments each. A total of 279 NES area segments 
were selected as shown in Table 1.

Third Stage Selection Housing Units

For each area segment selected in the second sampling stage, a listing had 
been made of all housing units located within the physical boundaries of the 
segment.  For segments with a very large number of expected housing units, 
all housing units in a subselected part of the segment were listed.  The 
final equal probability sample of housing units for the 2000 NES sample was 
systematically selected from the housing unit listings for the sampled area 
segments.

The 2000 NES sample design was selected from the 1990 SRC National Sample to 
yield an equal probability sample of 2269 listed housing units.  This total 
included 1972 housing units for the main sample and three reserve replicates 
of 99 cases each.  Table 2 below shows the assumptions that were used to 
determine the number of sample housing units.  The overall probability of 
selection for 2000 NES cross-section sample of households was f=0.00002116 or 
0.2116 in 10,000.  The equal probability sample of households was achieved 
for the 2000 NES sample by using the standard multi-stage sampling technique 
of setting the sampling rate for selecting housing units within area segments 
to be inversely proportional to the PPS probabilities used to select the PSU 
and area segment (Kish, 1965).

Fourth Stage Selection - Respondent Selection

Within each sampled 2000 NES occupied housing unit, the SRC interviewer 
prepared a complete listing of all eligible household members.  Using an 
objective procedure described by Kish (1949) a single respondent was then 
selected at random to be interviewed.  Regardless of circumstances, no 
substitutions were permitted for the designated respondent.
