The Net Undercount of Children in the Decennial Census Based on Demographic Analysis by Dr. William P. O’Hare O’Hare Data and Demographic Services, LLC COPAFS Presentation, June 7, 2013

Why Focus on The Undercount of Young Children in the Census? Young children have had high net undercount rates historically in the United States The net undercount rates of young Children have been increasing since 1980 There is very little systematic scientific evidence about this problem 2

Presentation and Terminology “ Undercount” versus “Difference” Net Undercount Here = Census - Estimates So negative number implies an undercount Positive number implies an overcount 3

How Do We Know Who Is Missed In The Census? Demographic Analysis (DA) Compares census results to an independent estimate based largely on birth and death certificate data Dual-Systems Estimates (DSE) Compares census results to a second follow-up survey conducted in selected areas (Called Census Coverage Measurement in 2010) 4

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What is Demographic Analysis? Estimates for population under age 75 are based on historical components of change for cohorts: [births, deaths, net international migration] P = B – D + NIM 99.6% of age 0-4 DA estimate is based on births 6

Components of DA Estimates for Age 0-4 Births = 21,076,000 Deaths = 148,000 Net International Migration = 244,000 Source: Census Bureau’s May 2012 DA Release 7

Limitations of DA Estimates Only National Level Data Only Black and Non-Black Data Historically Only Net Undercount/Overcount Figures No Estimation of Uncertainty 8

Overall Results of 2010 Decennial Census Look Good 9

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Good Overall Results Mask Important Differentials 11

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15 Difference Between 2010 Census and DA for People Under Age 5, by Sex, Race and Hispanic Origin NumberPercent TOTAL972, FEMALE471, MALE501, BLACK ALONE OR IN COMBINATION 247, HISPANIC414, NOT BLACK ALONE OR IN COMBINATION AND NOT HISPANIC 309, Note: Data on Hispanics is only available from the December 2012 DA Release. The “Not Black Alone or in Combination and Not Hispanic” category is not a category used by the Census Bureau. The racial categories used here are the Modified Race Categories where people who marked “some other race” in the Census are assigned to one of the major race categories.

How Does the Data form 2010 Compare to Earlier Censuses ? 16

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Key Findings Children have a net undercount & adults have a net overcount in 2010 Census Net undercount rates of children vary by age and race/ethnicity Younger children (under age 5) have the highest net undercount rate (4.6%) in 2010 and there is a net overcount for persons age 14 to 17 Black and Hispanic children account of most of high net undercount of young children and net overcount of 14-to-17-year-olds. High net undercount of young children is not new…..The age structure of net undercounts for children is relatively consistent since to 1980, net undercount rates for adults and young children fell, but 1980 to 2010, net undercount of adults fell while undercount of young children increased 19

KEY QUESTIONS 1.Why are there such high net undercount rates for young children in the census? 2.Why is there a net overcount rate for year- olds in the 2010 Census? 3.What accounts for the strong correlation between net undercount rates and age among children? 4.Why has the net undercount rate for young children increased since 1980? 20

Some Potential Reasons for High Net Undercount of Young Children 1.DA Estimates for young children are too high 2.Problems in collection and processing of data in Census 3.Time constraints among parents of young children 4.Young children live in households and families that are difficult to enumerate 21

Hypothesis - DA Estimates for young children are too high

Emigration of young children Pitkin and Parks (2005) hypothesize many children born to foreign-born (Mexican) women move to Mexico at a young age and are not picked up in DA emigration statistics. But, 0-4 year-olds missing in 2000 were found as year-olds in

Hypothesis - Systematic errors in census-taking or processing lead to net undercount of young children

The Census Questionnaire Continuation Form …Persons 7-12 need follow up (NRFU Persons 6-12) Young children are likely to be listed last on Census Questionnaire 10% of young children live in 7+ person households compare to 3% of adults 25

Several Improvements in the 2010 Census Form Added age to information collection on persons 6-12 on primary questionnaire Added a new “administrative” question about people who were left off roster Added instruction about “including babies” Added instruction about “child custody” Partnership with American Academy of Family Physicians and Planned Parenthood 26

Despite improvements, net undercount of young children increased between 2000 and 2010

Age Imputation Hypothesis - Too many people who should have had age imputed as 0- 4 got age imputed as (or other age groups) 28

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30 Hypothesis - Parents of young children don’t complete the census questionnaire because of time demands

Census Mail-Back Rates by Presence of Children and Family Type Census Mail-Back Rate Live Alone86% Single with adult roommates73% Single with kid(s)63% Married with no kids90% Married with kid(s)83% Source: Hillygus, Nie, Prewitt & Pals, 2006, Table 4.4

Hypothesis - Young children live in the kinds of households and living arrangements that are difficult to enumerate

Living Arrangements of Young Children 10 characteristics of Hard-to-Count populations identified by Census Bureau in Planning Data Base Young (age 0-4) Black and Hispanic children higher on every one of the 10 33

Summary Young Children have higher net undercount rate than any other age group in 2010 Young children have had relatively high net undercount rates since 1950 The trends in net undercount rates of young children and adults have diverged since 1980 Need to develop understanding of WHY young children have high net undercount rates in the census One focus of 2020 Census planning should be households with young black or Hispanic children 35

THANKS Contact Information William O’Hare 36