Overlooked and Undercounted - Insight Center for Community ...

28 — OVERLOOKED AND UNDERCOUNTED
Appendix A: Methodology and Assumptions
This study uses data from the 2007 American
Community Survey by the U.S. Census Bureau. The
American Community Survey (ACS), which shifted from
a demonstration program to the full sample size and
design in 2005, is a new approach to collecting census
data that eliminates the need for a long form in the 2010
Census. The ACS publishes social, housing, and economic
characteristics for demographic groups covering a broad
spectrum of geographic areas with populations of 65,000
or more in the United States and Puerto Rico.
The 2007 Public Use Microdata Sample (PUMS) is a
set of data files that contain records of a one percent
sample of all housing units that the survey interviewed.
For determining the PUMS sample size, the size of the
housing unit universe is the ACS estimate of the total
number of housing units. Nationally, the 2007 PUMS
data set contains a one percent sample size of 1,293,393
housing unit records (representing a housing unit
estimate of about 130 million households nationally);
in Mississippi, the 2007 ACS one percent sample size
is 39,217 housing units (representing a housing unit
estimate of 1,242,290 Mississippi households).
As of August 2006, the primary way to access data for
rural areas in the ACS is through Public Use Micro
Data Sample Areas (PUMAs), which are special, nonoverlapping
areas that partition a state. The Census
Bureau has produced 2007 ACS data products, which
contain selected demographic, social, economic, and
housing characteristics, for all 2,071 national PUMAs.
(See http://www.census.gov/acs/www/Products/PUMS/.)
Each PUMA, drawn by state governments for the Census
2000 sample PUMS files, contains a population of about
100,000. Mississippi, which has 82 counties, is partitioned
into 23 PUMAs, each of which has received 2007 ACS
estimates. In the instances when a single PUMA is in
more than one county, each county was weighted by
population and a new weighted average was calculated
to determine a Self-Sufficiency Standard specific to that
PUMA.
Since the Self-Sufficiency Standard assumes that all
adult household members work, the population sample
in this report includes only those households in which
there is at least one adult age 18-65 who is not disabled.
Thus, although the ACS sample includes households
that have disabled and/or elderly members, this report
excludes disabled/elderly adults and their income when
determining household composition and income.
Households defined as “group quarters” are also excluded
from this analysis. In total 743,859 non-disabled, nonelderly
households are included in this demographic
study of Mississippi.
ASSUMPTIONS FOR THE EXPANDED
SELF-SUFFICIENCY FAMILY TYPES
The 2008 Self-Sufficiency Standard for Mississippi was
calculated for 70 different family types in each county,
including combinations of up to two adults and three
children. However, to account for additional family types
found in the U.S. Census (three or more adults and/
or four or more children), the Self-Sufficiency Standard
for each county in Mississippi was expanded by an
additional 82 family types for a total of 152 family types.
In order to remain consistent with the Standard’s
methodology, it is assumed that all adults in one- and
two-adult households are working. Adults are defined
as all persons in a household (family and non-family)
who are between 18 and 64 years of age and able to work
(not disabled). Working adults are defined as those who
are employed at work or employed but absent from work
during the week preceding the survey, as well as people
in the Armed Forces. (Working adults also includes the
very small number of working teenagers 16 and over.)
Non-working adults include those who are unemployed
and looking for work as well as those who are not in
the labor force because they are retired or are in school,
or for some other reason. Therefore, all work-related
costs (transportation, taxes, and child care) are included
for these adults (if there are only two adults in the
households) in the household’s Standard. In Mississippi,
44% of the households have one worker, 50% have two
or more workers, and 6% have no workers. The actual
number of adults in the households ranges from one to