# Presentation: 404109

## Donna KostanichAssistant Division Chief Decennial Statistical Studies DivisionJohn F. LongDivision ChiefPopulation DivisionPrepared for:Joint FSCPE-SDC April 28, 2003 Meeting

** ****A.C.E. Revision II**

## Outline 

**Background**
**Methodology for A.C.E. Revision II        Estimates**
**Results – National**
** **

## Background

**March 2001 Decision**
**October 2001 Decision**

## Methodology

**Data Sources:**
**  ****Census 2000**
**  ****A.C.E. (E Sample, P Sample)**
**  ****A.C.E. Evaluations**
**  ****Demographic Analysis**
- (no additional field work)

## Methodology

**Correct Measurement Error**
- (A.C.E. & A.C.E. Evaluation Data)

**Further Study of Person Duplication**
- (A.C.E. & Census Data)

- To improve estimates of erroneous census enumerations (including duplication)
- 2.	To improve estimates of census omissions

## Methodology

**A.C.E. Revision II Estimation accounts for:**
**Correction of erroneous enumerations due to duplication**
**Correction in the coding of erroneous enumerations**
**Correction of census omissions due mostly to residence issues**
**Correction of census omissions for correlation bias**
**More variation in correct enumeration rates by using separate post-strata**

## Table 1: Change in Estimated Net Undercount (household population, in millions)

|  | Estimated Net Undercount |  | Change* |
| --- | --- | --- | --- |
| March 2001 A.C.E. Estimate | 3.26 |  |  |
| New Post-Stratification |  |  | +0.04 |
| Correcting Erroneous Enumerations:
  due to Duplication
  due to Recoding |  |  | 
-2.81
-2.43 |
| Correcting Census Omissions:
  for residence issues |  |  | 
-1.09 |
| Adjusting for Correlation Bias |  |  | +1.70 |
| Total Corrections to March 2001 A.C.E. Estimate |  |  | -4.59 |
| A.C.E. Revision II Estimate | -1.33 |  |  |

- *Shows the effect of adding in one revision at a time.  A different ordering of the revisions would result in slightly different intermediate effects, but yield the same overall net undercount estimate.  Estimated change in the net undercount is not the same as estimated additional erroneous enumerations or additional census omissions.

## Findings 

- A.C.E. Revision II is substantially different from the March 2001 A.C.E.
- The Census Bureau believes that A.C.E. Revision II estimates are considerably superior to the March 2001 A.C.E. estimates

## Table 2: Percent Net Undercount by Race/Hispanic Origin (household population)

| Characteristics | A.C.E. Revision II |  | A.C.E. March 2001 |  |
| --- | --- | --- | --- | --- |
|  | Est. (%) | S.E. (%) | Est. (%) | S.E. (%) |
| TOTAL | -0.49* | 0.20 | 1.18* | 0.13 |
| Non-Hispanic White | -1.13* | 0.20 | 0.67* | 0.14 |
| Non-Hispanic Black | 1.84* | 0.43 | 2.17* | 0.35 |
| Hispanic | 0.71  | 0.44 | 2.85* | 0.38 |
| Non-Hispanic Asian | -0.75 | 0.68 | 0.96 | 0.64 |
| Native Hawaiian and Pacific Islander | 2.12 | 2.73 | 4.60* | 2.77 |
| American Indian on Reservation | -0.88 | 1.53 | 4.74* | 1.20 |
| American Indian off Reservation | 0.62 | 1.35 | 3.28* | 1.33 |

- * Estimate is statistically significant from zero at the α = 0.10 level

## Findings 

- Reduction in net coverage error as compared to 1990
- Reduction in differential coverage error as compared to 1990

## Table 3: Percent Net Undercount for Race/Hispanic Origin 

| Characteristics | A.C.E. Revision II |  | 1990 PES |  |
| --- | --- | --- | --- | --- |
|  | Est. (%)  | S.E. (%) | Est. (%) | S.E. (%) |
| TOTAL | -0.49* | 0.20 | 1.61* | 0.20 |
| Non-Hispanic White 1 | -1.13* | 0.20 | 0.68* | 0.22 |
| Non-Hispanic Black | 1.84* | 0.43 | 4.57* | 0.55 |
| Hispanic | 0.71 | 0.44 | 4.99* | 0.82 |
| Non-Hispanic Asian 2 | -0.75 | 0.68 | 2.36* | 1.39 |
| Hawaiian or Pacific Islander 2 | 2.12 | 2.73 | 2.36* | 1.39 |
| American Indian on Reservation | -0.88 | 1.53 | 12.22* | 5.29 |
| American Indian off Reservation 1 | 0.62 | 1.35 | 0.68* | 0.22 |

- * Estimate is statistically significant from zero at the α = 0.10 level
**1 **For 1990, American Indian off Reservation was included in the Non-Hispanic White Race/Hispanic Origin Domain.  Therefore, the net undercount and standard error for these domains are repeated.
-  **2 **For 1990, Asian or Pacific Islander was a single Race/Hispanic Origin Domain.  Therefore, for Non-Hispanic Asian and for Hawaiian or Pacific Islander, the net undercount and standard error are repeated.

## Decision on Intercensal Population Estimates

- Base intercensal population estimates on the official Census 2000 results
- Technical concerns remain regarding the Accuracy and Coverage Evaluation (A.C.E.) Revision II methodology
- A.C.E. Revision II estimates should not be used to change the base for intercensal population estimates.

## Assessing Results of A.C.E. Revision II

- Uncertainty about the adjustment for  correlation bias
- Synthetic estimation error and choice of post-strata
- Inconsistencies with demographic analysis results for children
- Incompleteness of loss function analysis (total error model)

## Thank You

Technical Assessment and Detailed Reports
available at
http://www.census.gov/dmd/www/refroom.html

**Technical Assessment and Detailed Reports**
**available at**
- http://www.census.gov/dmd/www/refroom.html