Updating the SPM: Plans, 

Schedule and Using Households

Liana Fox

2023 FCSM Research & Policy Conference 

Oct. 26, 2023

The views expressed in this presentation, including those related to statistical, methodological, technical, or operational 

issues, are solely those of the author and do not necessarily reflect the official positions or policies of the U.S. Census 

Bureau. The author accepts responsibility for all errors. This presentation is released to inform interested parties of ongoing 

research and to encourage discussion of work in progress. This presentation has undergone more limited review than 

official publications. This presentation meets all of the U.S. Census Bureau’s Disclosure Review Board (DRB) standards and 

has been assigned DRB approval number CBDRB-FY24-SEHSD003-003. Do not cite or distribute without author permission.
Overview

2

• Thank you to the report authors & CNSTAT staff!

• All recommendations will be considered alongside research from 

Census/BLS and external researchers

• Census and BLS will continue working with our Interagency Technical 

Working Group (ITWG) on the SPM
ITWG Guidance

• SPM should continually evolve, improving due to changes in data, 

methodology or research

• Priority should be placed on “consistency between threshold and 

resource definitions, data availability, simplicity in estimation, stability 

of the measure over time, and ease in explaining methodology (ITWG, 

2010)”

• Changes were made in 2021 at 10-year anniversary of SPM

3
Established Process of Change

• Small adjustments/code updates can be made annually

• Large changes can be made every 5-10 years after multi-year period of 

research and stakeholder engagement

• Expectation that any changes will be detailed in a working paper

• Presented at 2+ academic conferences

• Presented at SPM ITWG meetings

• Presented at Spring Expert Meetings

• Tension between timeliness and appetite for change

• Transparency and public trust are crucial

4
Potential Timeline for SPM Changes

5

2023 2024 2025 2026

September 2025 – September 2026

Research showing the impact of the changes on 2024 

SPM rates - including research file.

September 2026

Release of 

Poverty report 

using new 

methodology

April 2023 – September 2026

Working papers and conference presentations discussing potential changes 

to the measure

Spring 2024

Expert Meeting

September 2025

ITWG decides on 

changes

Spring 2025

Expert Meeting
6

CNSTAT Panel Recommendation 2.7 
7

Unmarried 

Couple with 

Child

Mother of 

Woman with 

Child

Unrelated 

Individual

Current Resource Sharing Units for Poverty Measurement
8

Unmarried 

Couple with 

Child

Mother of 

Woman with 

Child

Unrelated 

Individual

Current Resource Sharing Units for Poverty Measurement

Family: Individuals 

residing together and 

related by birth, 

marriage and adoption
9

Unmarried 

Couple with 

Child

Mother of 

Woman with 

Child

Unrelated 

Individual

Current Resource Sharing Units for Poverty Measurement

SPM Unit: Families + 

unmarried partners and 

their relatives, 

unrelated children 

under 15 and foster 

children under 22
10

Unmarried 

Couple with 

Child

Mother of 

Woman with 

Child

Unrelated 

Individual

Current Resource Sharing Units for Poverty Measurement

Household: Everyone 

living together under 

one roof
11

Official Poverty Families Supplemental Poverty Units Household

Individuals residing together and 

related by birth, marriage and 

adoption

Individuals residing together and 

related by birth, marriage and 

adoption

Individuals residing together and 

related by birth, marriage and 

adoption

+ Unmarried partners and their 

relatives

+ Unmarried partners and their 

relatives

+ Unrelated children < 15 years old

+ Foster children <22 years old

+ Unrelated children < 15 years old

+ Foster children <22 years old

+Unrelated Individuals

Current Resource Sharing Units for Poverty Measurement
12

• More consistent with international poverty measurement

• More intuitive/easier to understand

• Increases transparency

• Simplicity--more transferability to other surveys

Motivation for Moving to the Household
13

• Largest impact on most vulnerable populations

• Do people living in households actually share resources?

• Housing and utilities

• Maybe food

• Likely not other essentials like clothing

Potential Concerns
14

No Change

96%

Change in 

Unit

4%

Who is Impacted?

Number of SPM 

Units/Household

% of People 

1 95.7%

2 2.9%

3+ 1.3%

Note: Details may not sum to totals due to rounding.

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
Types of Households Impacted

15

Number of SPM Families (2+ people)

Number of Solo Units 0 1 2

0 -- -- 4.0%

1 -- 32.8% 1.0%

2 31.9% 6.9% 0.6%

3 12.6% 1.9% S

4 5.7% S --

5+ 2.0% S --

S: Estimate is withheld due to small sample size.

Note: Details may not sum to totals due to rounding.

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
Types of Households Impacted

16

Number of SPM Families (2+ people)

Number of Solo Units 0 1 2

0 -- -- 4.0%

1 -- 32.8% 1.0%

2 31.9% 6.9% 0.6%

3 12.6% 1.9% S

4 5.7% S --

5+ 2.0% S --

S: Estimate is withheld due to small sample size.

Note: Details may not sum to totals due to rounding.

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 

Roommates—All 1 person SPM Units: 52.3%
Types of Households Impacted

17

Number of SPM Families (2+ people)

Number of Solo Units 0 1 2

0 -- -- 4.0%

1 -- 32.8% 1.0%

2 31.9% 6.9% 0.6%

3 12.6% 1.9% S

4 5.7% S --

5+ 2.0% S --

S: Estimate is withheld due to small sample size.

Note: Details may not sum to totals due to rounding.

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 

Roommates—All 1 person SPM Units: 52.3%

Multiple 

Families: 

4.0%
Types of Households Impacted

18

Number of SPM Families (2+ people)

Number of Solo Units 0 1 2

0 -- -- 4.0%

1 -- 32.8% 1.0%

2 31.9% 6.9% 0.6%

3 12.6% 1.9% S

4 5.7% S --

5+ 2.0% S --

S: Estimate is withheld due to small sample size.

Note: Details may not sum to totals due to rounding.

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 

Roommates—All 1 person SPM Units: 52.3%

Multiple 

Families: 

4.0%

Family + Extra: 43.7%
19

Demographics of Individuals Impacted

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 

Under 18

8%

18-26

35%

27-34

16%

35-44

12%

45-54

10%

55-64

11%

65+

8%

Age

Owner with 

mortgage, 

25%

Owner, no 

mortgage, 

15%

Renter, 60%

Housing Tenure Status

Inside 

principal 

cities, 44%

Outside 

principal 

cities, 47%

Outside 

MSAs, 9%

Residence
20

Impact on 2022 SPM Poverty Rates

* An asterisk following an estimate indicates difference is statistically different from zero at the 90 percent confidence level.

Note: Details may not sum to totals due to rounding

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
21

Impact on 2022 SPM Poverty Rates

* An asterisk following an estimate indicates difference is statistically different from zero at the 90 percent confidence level.

Note: Details may not sum to totals due to rounding

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
22

Impact on 2022 SPM Poverty Rates

* An asterisk following an estimate indicates difference is statistically different from zero at the 90 percent confidence level.

Note: Details may not sum to totals due to rounding

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
23

Impact on 2022 SPM Poverty Rates

* An asterisk following an estimate indicates difference is statistically different from zero at the 90 percent confidence level.

Note: Details may not sum to totals due to rounding

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
24

Impact on 2022 SPM Poverty Rates

* An asterisk following an estimate indicates difference is statistically different from zero at the 90 percent confidence level.

Note: Details may not sum to totals due to rounding

Source: U.S. Census Bureau, Current Population Survey, 2023 Annual Social and Economic Supplement (CPS ASEC). 
Additional Considerations and Next Steps

• Continued work on:

• Change in equivalence scales ( nn)

• Look at additional years

• Additional exploration of unit changers

• Next Steps:

• Integrate thresholds based on household units

• Release working paper

25
LIANA.E.FOX@CENSUS.GOV

Thank You