# Presentation: 710246

## ACS Multi-year Research

- Jerry Deichert
- Center for Public Affairs Research
- University of Nebraska - Omaha
- State Data Center Annual Meeting
- October 12, 2007

## Issues we have faced using multi-year estimates

- What do we call the time period?
- How do we present the data?
- What are the relative sizes of the MOE (Should we use the estimates)?
- If we have a choice, should we use 1-year, 3-year, or 5-year estimates?
- Can we use the data for counts for census tracts or block groups?
- How do we compare time periods?

## How do we present the data?

## Slide 4

## Slide 5

## Slide 6

## Slide 7

## Slide 8

## Slide 9

## Slide 10

## Slide 11

## What are the relative sizes of the MOE (Should we use the estimates)?

## Persons in Poverty for Omaha, NE: 1-year Estimates From 1997-2005 ACS

| Omaha, NE | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Individuals in Poverty | 45,217 | 45,366 | 42,236 | 44,670 | 41,369 | 47,133 | 50,368 | 51,567 | 57,020 |
| Persons for Whom Poverty is Determined | 339,977 | 342,149 | 371,509 | 372,674 | 375,353 | 381,695 | 371,799 | 371,061 | 371,917 |
| Percentage | 13.3 | 13.3 | 11.4 | 12.0 | 11.0 | 12.3 | 13.5 | 13.9 | 15.3 |
| Annual Pov MOE (+/-) |  |  | 0.8 | 1.0 | 1.0 | 1.5 | 1.6 | 1.5 | 1.5 |

## Persons in Poverty for Omaha, NE: 3-year Estimates From 1997-2005 ACS

| Omaha, NE | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Single-year estimates | 13.3 | 13.3 | 11.4 | 12.0 | 11.0 | 12.3 | 13.5 | 13.9 | 15.3 |
| 3-year calculated estimates |  |  | 12.6 | 12.2 | 11.5 | 11.8 | 12.3 | 13.3 | 14.3 |
| Actual 3-yr estimates released |  |  |  |  | 11.4 | 11.7 | 12.1 | 13.2 | 14.2 |
| Actual 3-yr MOE |  |  |  |  | 0.5 | 0.7 | 0.8 | 0.8 | 0.8 |

## Persons in Poverty for Omaha, NE: 5-year Estimates From 1997-2005 ACS

| Omaha, NE | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Single-year estimates | 13.3 | 13.3 | 11.4 | 12.0 | 11.0 | 12.3 | 13.5 | 13.9 | 15.3 |
| 5-year calculated estimates |  |  |  |  | 12.1 | 12.0 | 12.1 | 12.6 | 13.2 |
| Actual 5-yr estimates released |  |  |  |  |  |  | 11.9 | 12.5 | 13.2 |
| Actual 5-yr MOE |  |  |  |  |  |  | 0.5 | 0.5 | 0.6 |

## Comparison of 1-year, 3-year, and 5-year Estimates of the Percentage of Persons in Poverty for Omaha, NE: 1999-2005 ACS

|  | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Single-year estimate | 11.4 | 12.0 | 11.0 | 12.3 | 13.5 | 13.9 | 15.3 |
| Single-year MOE | 0.8 | 1.0 | 1.0 | 1.5 | 1.6 | 1.5 | 1.5 |
| Three-year estimate |  |  | 11.4 | 11.7 | 12.1 | 13.2 | 14.2 |
| Three-year MOE |  |  | 0.5 | 0.7 | 0.8 | 0.8 | 0.8 |
| Five-year estimate |  |  |  |  | 11.9 | 12.5 | 13.2 |
| Five-year MOE |  |  |  |  | 0.5 | 0.5 | 0.6 |

## Ratio of MOE to Estimate of Median Household Income for Douglas County Nebraska: 2001-2005 Multi-year Estimate

|  | Number of Areas | Median Ratio | Highest Ratio | Lowest Ratio |
| --- | --- | --- | --- | --- |
| Census Tracts | 146 | 0.129 | 1.423 | 0.029 |
| 
Block Groups | 466 | 0.242 | 2.122 | 0.032 |

## Slide 18

## If we have a choice, should we use 1-year, 3-year, or 5-year estimates?

- Cynthia Taeuber in *American Community Survey Data for Community Planning* says, “Personally, if I have the option, I use the 3-year estimates.  They are a compromise between the timely but less stable single-year estimates and the stable but lagging 5-year estimates.”

## Can we use the data for counts for census tracts or block groups?

## How do we compare time periods using multi-year estimates?

- The 2003-2005 estimate overlaps with the 2002-2004 estimate.
- To have an independent estimate you would have to compare to 2000-2002.
- Comparing 2003-2005 to 2002-2004 is the equivalent of comparing single year 2005 to 2002

## Comparing 3-year Estimates of the Percentage of Persons in Poverty for Omaha, NE: 2002-2004 to 2003-2005

|  | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Single-year estimate | 11.4 | 12.0 | 11.0 | 12.3 | 13.5 | 13.9 | 15.3 |
| 
 |  |  |  |  |  |  |  |
| Three-year estimate |  |  | 11.4 | 11.7 | 12.1 | 13.2 | 14.2 |
|  |  |  |  |  |  |  |  |
| Five-year estimate |  |  |  |  | 11.9 | 12.5 | 13.2 |
|  |  |  |  |  |  |  |  |

- Overlap