Committee Agenda Date iFebruaty 16. 2005

County of Santa Clara
Office of the County Executive
Office of Budget and Analysis

CSFC-CE02 021605

Prepared by: Autumn Arias
Budget and Public Policy
Analyst
DATE:

February 16, 2005

TO:

Supervisor James T. Beall, Jr., Chairperson
Supervisor Don Gage, Vice-Chairperson
Children, Seniors & Families Committee

FROM:
Sandra Y. Nathan

Deputy County Executive

SUBJECT: Report Back on Referral Regarding U.S. Census Information for Seniors in each
Supervisorial District

RECOMMENDED ACTION

Accept report back on referral from Children, Seniors and Families Committee, regarding
census infonnation on the number of seniors eligible for the Senior Nutrition Program, and
living in poverty, in each supervisorial district.
FISCAL IMPLICATIONS

There are no fiscal implications.

Board of Supervisors: Doriald F. Gage, Blanca Alvarado, Pete McHugh. Jim Beall, Liz Kniss
County Executive: Peter Kutras Jr.
1

Committee Agenda Date ;February 16, 2005

CONTRACT HISTORY

None.

REASONS FOR RECOMMENDATION

On October 20, 2004 the Children, Seniors and Families Committee directed the County

Executive's Office to work with the Planning Office and the Department of Aging and Adult
Services to provide information regarding the number of seniors, age 60+, who are eligible for
the Senior Nutrition Program, and also the number of this senior population living in poverty.
The referral was made during the Committee discussion on the Senior Nutrition Program
funding report and geographic distribution of seniors within the County.
Staff from the following departments met to discuss the assumptions that would need to be
made in order to develop this information: County Executive's Office, Cross Systems
Evaluation Division, Planning Office, and Department of Aging and Adult Services, Senior
Nutrition Program. In addition, the Public Health Department was consulted due to the

expertise it has developed in analyzing U.S. Census Bureau data. The information is not
readily available through the U.S. Census Bureau database, because poverty information is
only available at the Census Tract geographical level, which does not correspond precisely to
Supervisorial Districts.

Supervisorial Districts were created through the Redistricting Program that occurred in 2001.
These Districts were created by assembling Census Blocks and establishing boundaries
coincident with Census Block boundaries. However, as previously stated, poverty information

is collected by the U.S. Census at the larger geographical level of Census Tracts. Supervisorial
Districts split a number of Census Tracts even though they follow the boundaries of the
smaller Census Blocks.

"Estimating Methodo.Lo.gy"

The Planning Office developed an "estimating methodology," as described in depth in the
attached memorandum from Steven Golden, Planner III. There are a total of 341 Census

Tracts in the County. Of these, 285 occur entirely within one Supervisorial District. The
remaining 56 tracts are split between two Supervisorial Districts within the County. All of the
split Census Tracts were placed into one of three categories for the purpose of this analysis:

Board of Supervisors: Donald F. Gage, Blanca Alvarado, Pete McHugh,Jim Beall, Liz Kniss
Counts/ Executive: Peter Kutras Jr.
2

Committee Agenda Date February 16, 2005

20 Split Census Tracts have 100% of the total population in the tract living in one
Supervisorial District. Therefore, all of the population in these tracts was assigned to
the district they lived in.

18 Split Census Tracts have over 90% of the population in the tract living in one
district. Therefore, all of the data in these tracts was assigned to the district containing
over 90% of the population.

18 Split Census Tracts have less than 90% of the population living in each district in the
tract. Therefore, the data was assigned to each district according to the percentage of
total population for that section of the tract.
Another estimation was needed for 14 of the Census Tracts, where confidentiality of reporting

requirements suppressed the data regarding persons 60 years and older living in poverty.
Therefore, in these 14 tracts, data from persons 65 and over in poverty was used, instead of
age 60 and over. It is likely that for these tracts the number used is a slight underestimate.

The poverty definition and determination of poverty status used by the U.S. Census Bureau is
described in detail on pages 2-3 of the attached memorandum. Basically, a weighted average
threshold is used to determine an average threshold for a given family size. Poverty status is
then determined for every person except institutionalized people, those living in military
group quarters or college dormitories, and unrelated individuals under 15 years old.
Summary of Data

Using the methodology described above, the Planning Office has determined the following
data per Supervisorial District. All persons age 60 years and over are eligible for participation
in the Senior Nutrition Program; therefore, the column of"Total People 60 and Over"
represents the number of eligible people per district.

Board of Supervisors: Donald F, Gage, Blanca Alvarado, Pete McHugh, Jim Beall, Liz Kniss
County Executive: Peter Kutras Jr.
3

Committee Agenda Date :February 16, 2005

District

Total People 60

Percent of Total People 60

People 60 and
*

and Over*

Over in Poverty

and Over in Poverty*

Distriet 1

40,380

1,948

14.9%

District 2

33,907

3,659

27.9%

District 3

36,085

2,196

16.8%

District 4

49,107

3,139

24.0%

District 5

58,541

2,159

16.5%

TOTAL

218,020

13,101

100%

* As calculated using the "Estimating Methodology

The values reported above are only an estimation based on the methodology used. It is
possible that the technique used to assign data among split Census Tracts using proportions of
total population split between the traets does not aecurately represent the number of persons
60 and over in poverty in eaeh Supervisorial Distriet.

There is uneertainty that total population and persons 60 and over in poverty have a
eorrelation beeause local characteristics of neighborhoods and communities play a key role.
For these reasons, ranges are reported below:
Range: Total Persons

Range: Persons 60

60 and Over*

and Over in Poverty

Distriet 1

36,136-41,891

1,663 - 2,054

District 2

32,647-37,485

3,557 - 3,938

District 3

33,494- 37,168

1,963 - 2,280

District 4

44,246-54,431

2,953 - 3,414

District 5

56,544-61,998

2,110-2,270

Distriet

*

*

As calculated using the "Estimating Methodology'

Board of Supervisors: Donald F. Gage, Blanca Alvarado, Pete McHugh,Jim Beall, Liz Kniss
County Executive: Peter Kutras Jr.
4

Committee Agenda Date :February 16, 2005

Use of Geographic Information Systems ^GIS) as a Resource

The Planning Office estimates that approximately 50 hours were needed to prepare this
methodology and develop the data presented in this report. The majority of the time was spent
using GIS to analyze Census Tracts, developing the methodology, and executing the splitting
of Census Tracts into appropriate Supervisorial Districts. This methodology may be used to
estimate other population demographics, however, with the understanding of the potential
inaccuracies and uncertainty involved.
ATTACHMENTS

• Memorandum From Planning Office

Board of Supervisors: Donald F. Gage, Blanca Alvarado, Pete McHugh, Jim Beall, Liz Kniss
County Executive: Peter Kutras Jr.
5

DATE: January 10, 2005
TO; Autumn Arias, Michael Bobadilla, Amando Cablas

FROM: Steven Golden, Planning Office

RE: Census Data for Senior Nutrition Program Referral from CSFC

This memo describes the process used to estimate the number of people 60 years of age and over
who live in poverty by Supervisorial District. This memo is being sent via e-mail with an
attached file named ‘Poverty60_SupDistrict.xls” that has more detailed data.
Estimating Methodology'

Supervisorial Districts were previously created through the Redistricting Program that occurred
in 2001. These districts were created by assembling Census Blocks and establishing boundaries
coincident with Census Bloek boundaries. However, the U.S. Census Bureau does not release

poverty based data at the Census Block geographical level. Poverty based data is available at the
Census Tract geographical level. As a result, the Census Tract based data was used, but Census
Tract boundaries are not coincident with Supervisorial District boundaries (i.e. Supervisorial
Districts split a number of Census Tracts). Consequently, the data had to be estimated using the
most practical and appropriate method available. The derived method follows:
• For those Census Tracts that were entirely located in a particular Supervisorial District,
100% ofthe data went to that particular District.

• There were a total of 56 split Census Tracts between two Supervisorial Districts. There
were 3 categories for estimating data for these Census Tracts as follows:
o
100% of total population - For 20 of these Census Tracts, one section of the split
Census Tract had 100% of the total population, therefore 100% of the data was
assigned to one Supervisorial District.
o

o

>90% oftotal population - Eighteen Census Tracts were split where >90% of the
total population were located in one section of the split Census Tract. In these
cases, all of the data was assigned to the Supervisorial District containing the
portion of the Census Tract that had >90% of the population.
<90% of total population - Eighteen Census Tracts were split where <90% of the
total population were located in either section ofthe split Census Tract. In these
cases the data was assigned to each Supervisorial District according to the
percentage of total population for that section ofthe Census Tract.

Data was obtained from Summary File 3(sample population), 2000 Census, U.S. Census Bureau
using the Advanced Query option ofthe U.S. Census Bureau’s online database, American
FactFinder. Because of confidentiality reporting requirements, there were 14 Census Tracts
where the data (persons 60 years and over in poverty) was suppressed. In lieu of this and

because of other reporting requirements, data from persons 65 and over in poverty was used. It
is likely that for these 14 Census Tracts the number used is a slight underestimate.

Poverty Definition

The Census Bureau uses the federal government's official poverty definition. The Office of
Management and Budget's(OMB's) Directive 14 prescribes this definition as the official poverty
measure for federal agencies to use in their statistical work. The following is from the U.S.
Census Bureau’s website:

How Poverty Status is Determined

The poverty status of families and unrelated individuals in 1999 was determined using 48 thresholds
(income cutoffs) arranged in a two dimensional matrix. The matrix consists of family size (from 1
person to 9 or more people) cross-classified by presence and number of family members under 18
years old (from no children present to 8 or more children present). Unrelated individuals and 2-person
families were further differentiated by the age of the reference person (RP)(under 65 years old and 65
years old and over).

To determine a person's poverty status, one compares the person's total family income with the
poverty threshold appropriate for that person's family size and composition (see table below). If the
total income of that person's family is less than the threshold appropriate for that family, then the
person is considered poor, together with every member of his or her family. If a person is not living
with anyone related by birth, marriage, or adoption, then the person's own income is compared with
his or her poverty threshold.

Weighted average thresholds. Even though the official poverty data are based on the 48 thresholds
arranged by family size and number of children within the family, data users often want to get an idea
of the "average" threshold for a given family size. The weighted average thresholds provide that
summary. They are weighted averages because for any given family size, families with a certain
number of children may be more or less common than families with a different number of children. In
other words, among 3-person families, there are more families with two adults and one child than
families with three adults. To get the weighted average threshold for families of a particular size,
multiply each threshold by the number of families for whom that threshold applies; then add up those
products, and divide by the total number of families who are of that family size.
For example, for 3-person families, 1999 weighted thresholds were calculated in the following way using
information from the 2000 Current Population Survey:
Number of

Family type

Threshold

families

No children (three adults)

5,213

$13,032 = $67,935,816

One child (two adults)

8,208

$13,410 = $110,069,280

Two children (one adult)

2,656

$13,423 = $35,651,488

Totals

16,077

$213,656,584

Source: Current Population Survey, March 2000.

Dividing $213,656,584 by 16,077 (the total number of 3-person families) yields $13,290, the weighted
average threshold for 3-person families. Please note that the thresholds are weighted not just by the
number of poor families, but by all families for which the thresholds apply: the thresholds are used to
determine which families are at or above poverty, as well as below poverty.

Individuals for whom poverty status is determined. Poverty status was determined for all people
except institutionalized people, people in military group quarters, people in college dormitories, and
unrelated individuals under 15 years old. These groups also were excluded from the numerator and
denominator when calculating poverty rates. They are considered neither "poor" nor "nonpoor."

Specified poverty levels. For various reasons, the official poverty definition does not satisfy all the
needs of data users. Therefore, some of the data reflect the number of people below different
percentages of the poverty level. These specified poverty levels are obtained by multiplying the official
thresholds by the appropriate factor. For example, the average income cutoff at 125 percent of the
poverty level was $21,286 ($17,029 x 1.25) in 1999 for family of four people.

Poverty Thresholds in 1999 by Size of Family and Number of Related Children Under 18 Years
Old

(Dollars)
Related children under 18 years
Eight

Weighted
Average

None

Two

One

Three

Four

Five

Six

Seven

One person
(unrelated
individual)

or

more

Threshold

Size of Family Unit

8501

Under 65

8667

8667

7990

7990

years old
65 years old
and over

10869

Two People

i

Householder
11214

11156

11483

10075

10070

11440

Three people

13290

13032

13410

Four people

17029

17184

17465

16895

Five people

20127

20723

21024

20380

19882

19578

Six people

22727

23835

23930

23436

22964

22261

Seven people

25912

27425

27596

27006

26595

25828

24934

Eight people

28967

30673

30944

30387

29899

29206

28327

27412

27180

Nine people

34417

36897

37076

36583

36169

35489

34554

33708

33499

under 65

years old
Householder

65 years old
and over

13423
16954

21845
23953

or more

Summary of Data
Total People 60

People 60 and

Percent of Total People 60

and Over*

Over in Poverty*

and Over in Poverty

District 1

40,380

1,948

14.9%

District 2

3,659 '

27,9%

District 3

33,907
36,085

2,196

16.8%

District 4

49,107

3,139

24.0%

District 5

58,541

2,159

16.5%

218,020

13,101

100%

Total

I

*: As calculated using the "Estimating Methodology'

The values reported above are only an estimation based on the methodology used. It is possible
that the technique used to assign data amongst split Census Tracts using proportions of total
population split between the Census Tracts does not accurately represent the number of persons

32208

60 and over in poverty in each Supervisorial District. There is uncertainty that total population
and persons 60 and over in poverty have a correlation because local characteristics of
neighborhoods and communities play a key role. For these reasons, ranges are being reported
below:

Range: Total Persons

Range: Persons 60

60 and Over*

and Over in Poverty*

District 1

36,136

41,891

District 2

^^47

37,485

1,663
3.557

2,054
3,938

District 3

33,494 ' i~ 37,168
44,246 .-! 54,431

1,963
2,953

T-i 2,280

District 4
District 5

56,544 !-r61,998

2,110

2^270

...

*: As calculated using the "Estimating Methodology" 1,

3,414