data
w125883124
DemographyFall191.pptx
Demography
The scientific study of population.
Decennial Census collected every 10 years since 1790.
Worlds largest data set.
Determines the number of congressional representatives and allocation of federal funds.
American Community Survey (ACS) sample that supplements the census with ongoing data gathering on additional topics (housing, education, occupation, etc.).
Center for Disease Control (CDC)
Data on diseases, life expectancy, drug use, obesity, behaviors, etc.
Records vital stats (births, deaths, marriages & divorces)
Various surveys on such topics as immigration, personal finance, political affiliation, and attitudes.
Demography
Census: Topics, Population, Data, More Population Data
CDC: Diseases and Conditions, Data Statistics, Vital Stats
Demography
Issues with Census Data:
Self enumerations may undercount specific groups
Privacy issues, mistrust of government, and/or inability to locate may limit participation by minorities, inner city residents, homeless, and transients.
Reduces political representation and funding.
Prisoners count as residents of the prison
Prisoners are disproportionally adult minority males, skewing geographical demographics.
May add to political representation and funding in location of prison.
Inter-census year data are estimates only
Population changes are based on county birth and death data.
County housing records are then used to allocate the population growth to individual cities within each county.
Creates large gaps between decennial headcounts relative to the prior year.
Demography
Issues with Census Data:
Privacy
Data is adjusted to preserve anonymity without sacrificing demographic patterns.
Identities of respondents are removed.
Income values are rounded off.
Outliers are averaged together.
Characteristics of respondents are swapped.
Researching Undocumented Immigrants
Lowest estimates come from surveys since many are hesitant to reveal their undocumented status out of fear of deportation.
Medium estimates come from a residual approach that involves subtracting legal immigrants from the entire foreign-born population in the U.S.
Highest estimates come from Border Patrol extrapolations measuring arrests at the border; however, these are biased since the same individual may be arrested multiple times.
Accurate counts are critical!
Undocumented residents count for congressional apportionment
Allows for better cost/benefit analysis of migrants and policy prescriptions.
Demography
Researching Race and Ethnicity
Non-scientific conflations of biological, national origins, and/or linguistic traits.
Census provides multiple categories of race but no “multi-racial” category.
Who is “Black” or “African American”
Typically identified by skin color.
NAACP estimated that despite 70% of Blacks being multi-racial, only 3% checked more than one box.
CDC’s Vital Statistics definition historically assigned the race of the non-white parent to the child; since 1989 they have used the mother’s race (led to an increase in black infant mortality rates).
Who is “Asian”
Typically identified by country of origin.
Write-in surveys are especially problematic for uneducated groups, causing an undercount.
Who is “Hispanic”
Broader definition using cultural characteristics
Acquired an entirely separate question on Census form.
Who is “Arab” or “Middle Eastern”
No separate category in census.
Summary
Inconsistent results, lack of clear definition cause people to often choose different categories at different times in their lives.
Imbalances in political representation and funding for certain groups.
Race at death often involves a visual inspection of the body by a mortician or physician.
Death rates often use mortician/physician evaluation of race in numerator but census evaluation in denominator.
Demography
Researching LGBT Community
1948 Kinsey study contended 10% of the population is homosexual.
Sample bias: males studied were incarcerated and included prostitutes and sex offenders.
1992 national opinion poll showed 2.8% (identify as gay), 6% (attracted to same sex), and 9% (had at least one homosexual experience since puberty).
Self-selection bias: volunteers may not have been representative of the larger population.
1993 Yankelovich Consumer Survey found 5.7% of respondents were gay.
Self-selection bias: volunteers may not have been representative of the larger population.
2011 Researcher Gary Gates averaged four national and two state surveys conducted after year 2000 and concluded approximately 3.5% self identify as Lesbian, Gay, or Bisexual.
Sample bias: one of the surveys was in California (highest gay population in the U.S.)
Summary
Sample and self-selection biases limit the credibility of many studies.
Surveys conducted in specific geographies may not be representative of the larger population.
Personal nature implies survey method (online, phone, mail, personal interview) may yield inconsistent results.
Phrasing: different interpretations of “Transgender”, “Bi”, “Homosexual”, “Gay”.
Sexual behavior may differ from sexual orientation and gender identity.
Demography
Researching Households
Census identifies “Household” by the housing unit, not the relationship of inhabitants.
“Family” vs. “Non-Family” households: family is defined as two or more people related by birth, marriage, or adoption and residing together.
Many research projects analyze “family households”, omitting young single and/or cohabiting individuals and creating a bias in income, housing, education, employment and other stats.
Increasing gay marriages suggest Household composition may shift from “Non-family” to “Family”.
Demography
Researching Marriage and Divorce
Since the 1980s divorces per 1000 people have fallen.
Stat controls for population changes but not the number of marriages.
Over the same time frame the number of marriages has fallen too.
Is the lower number of divorces because of less marriages failing or just less marriages?
Longitudinal studies estimate the marriage survival rate
For marriages occurring in the 1970s the 25-year rate was 48% (typical media point that half of all marriages fail)
From 2006-2010 the survival rate for first marriages was:
10 year: 68% for women and 78% for men.
20 year: 52% women and 56% men.
Details Matter
Divorce rates are much lower for those that marry older compared to those that marry young.
Decline in married households is partly due to a substitution toward long-term cohabitation.
In 2002 >20% of cohabitating couples had lived together for >5 years, suggesting a long-term arrangement.
