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Mar 12: Demography, Labor Migration, Displacement Tiebout, Charles M. "A Pure Theory of Local Expenditures." Journal of Political Economy, Vol. 64, No. 5, October 1956, pp. 416-424. [Library reserve s]
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Mar 12: Demography, Labor Migration, Displacement Tiebout, Charles M. "A Pure Theory of Local Expenditures." Journal of Political Economy, Vol. 64, No. 5, October 1956, pp. 416-424. [Library reserves] Frey, William H. Immigration and Internal Migration "Flight from US Metropolitan Areas: Toward a New Demographic Balkanization." Urban Studies, Vol. 32, No. 4-5, May 1995, pp. 733-757. [Library reserves] Florida, Richard. 2002. Bohemia and economic geography, Journal of Economic Geography 2 (Jan): 55-71. [c-tools "Resource" section] Florida, Richard. 2009. How the Crash will Reshape America. The Atlantic Monthly; March. [online] see also: Myers, Dowell and Lee Menifee . "Population Analysis," in The Practice of Local Government Planning, 3rd edition, edited by Charles J. Hoch, Linda C. Dalton and Frank S. So International City/County Management Association, 2000, pp. 61-86. [Library reserves] excerpts from Bill Bishop, The Big Sort [link] links: USCensus:Geographical Mobility/Migration • Migration Data and Reports • migration tables in the 2009 Statistical Abstract • United Van Lines 2008 Migration Study the American Moving & Storage Association CS Monitor: "Patchwork Nation" Andrea Coombes, Retirees Who Relocate Often Opt For Homes in Metropolita Areas, Wall Street Journal, March 31, 2006. [link]
Fertility Mortality economic demography migration
- Be born - give birth - migrate - (attract a migrant) - die
The next generation is born… migration migration space birth migration migration migration migration migration time Imagine a two time-space dimensional world (one time dimension, one space dimension) college birth Comes Home After college death Moves to retirement community Moves to another city for job
migration migration space migration migration migration migration migration time Imagine a two time-space dimensional world (one time Dimension, one space dimension) birth birth death
space birth time Do you need to know the path or just the start and finish? birth death
Demography: the study of life EVENTS. Individuals are “at risk” of experiencing these events.
The frequency of events: events happen at rates: number of events of a specific type in a given time period ---------------------------------------------------------- Number of people at risk of experiencing that type of event in the given time period. Rate =
The frequency of events: events happen at rates: occurrence -------------- exposure Rate =
EXAMPLE: CRUDE DEATH RATE Total number of deaths in a given year ---------------------------------------------------------- Total population in that year CDR =
EXAMPLE: CRUDE BIRTH RATE Total number of births in a given year ---------------------------------------------------------- Total population in that year CBR =
EXAMPLE: CRUDE BIRTH RATE (per 1,000 pop) Total number of births in a given year ------------------------------------------------- Total population in that year CBR = * 1,000
Total number of births in a given year ------------------------------------------------- Total population in that year CBR = * 1,000
A comparison of: CRUDE VERSUS AGE-SPECIFIC RATES Crude Birth Rate General Fertility Rate Age-Specific Fertility Rate Total number of births in a given year _______ Total population in that year Number of Births _____________ Number of Women ages 15 - 49 Number of Births to womenages 20 - 24 ______________ Number of Women ages 20 - 24
“The Demographic Transition” http://www.populationaction.org/resources/factsheets/images/demographicTransit_fs.jpg http://www.geo.oregonstate.edu/classes/geo300/trans/demot.jpg
TOTAL FERTILITY RATE (TFR) Source: CDC http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5449a5.htm
Fecundity: The physiological capacity of a woman to produce a child [a theoretical upper limit] Fertility: The actual reproductive performance of an individual, a couple, a group, or a population. [fecundity adjusted by social/cultural practices and events, including birth control, nutrition, delayed childbirth, etc.]
Demography: the study of life EVENTS. Individuals are “at risk” of experiencing these events. Events occur in a temporal-spatial context.
Right now, each of you can be located at a specific: Tn time (1 dimension) Sn space (3-dimensions [x,y,z], or 2 on a flat surface [x,y], such as a map or the earth’s surface) When you were born, you were located at a specific: T0 time S0 space From these two we can get: Your age: Tn - T0 Your net migration: Sn - S0 (and with more, intermediate time points, we could also determine the specific legs of your migratory path to Ann Arbor)
Having data over time is known as longitudinal data • if we follow age groups (cohorts) over time, then this is known as cohort data • Here: randomly pick three every 10 years • special case: if we follow the same individuals in a cohort over time, then this is known as panel data • Here: pick the same three people every ten years 1970 1980 1990 2000 1970 1980 1990 2000 Birth Age 10 Age 20 Age 30 Birth Age 10 Age 20 Age 30
Example of a cohort study "Give me the child at seven, and I will give you the man.”
10 Leading Causes of Death in 2001 heart disease 2. cancer 3. stroke 4. chronic lower respiratory disease 5. accidents 6. diabetes 7. pneumonia/flu 8. Alzheimer's disease 9. kidney disease Suicide Source: Centers for Disease Control and Prevention (CDC), National Center for Health Statistics
http://www.cdc.gov/nchs/data/ahcd/agingtrends/06olderpersons.pdfhttp://www.cdc.gov/nchs/data/ahcd/agingtrends/06olderpersons.pdf
Life Expectancy From birth…
From birth… Life expectancy of a village Of ten people… 592 person-years ___________ 10 persons = 59.2 years
National Vital Statistics Reports, Vol. 54, No. 14, April 19, 2006
Death Rates, by Age Group, in the United States, 1998 The first year of life is high risk Once you get through the teenage years, the risk of death stops increasing -- at least for a few years. Age 10 is the safest time of life
Life Expectancies (at birth) in the United States, in years (e0) for the year 2001, by Race and Sex Male FemaleTOTAL All Races 74.4 79.8 77.2 White 75.0 80.2 77.7 Black 68.6 75.5 72.2 Source: National Vital Statistics Reports, Vol. 52, No. 14, February 18, 2004 33 url: http://www.cdc.gov/nchs/data/dvs/nvsr52_14t12.pdf
http://www.cdc.gov/nchs/fastats/pdf/nvsr50_06tb12.pdf; FROM http://www.cdc.gov/nchs/fastats/lifexpec.htm National Vital Statistics Report,Vol.50,No.6,March 21,2002 33 Table 12.Estimated life expectancy at birth in years,by race and sex:Death-registration States,1900 –28,and United States,1929 –99 [For selected years,life table values shown are estimates;see Technical notes.Beginning 1970 excludes deaths of nonresidents of the United States;see Technical notes ]
Demography for planners? absolute population levels in the future
but more importantly: The components of population. Demand for services vary by age, sex, family status, immigration status, etc.
Examples: demand for housing ,roads, schools, child care, special-needs housing.
Demographers thus speak of Age-specific rates (e.g., age-specific migration rates)
What is the implication for social policy (e.g., school funding, job training, pension plans) of dramatic differences in age-specific racial/ethnicity composition in places like California and Florida?
US Census 2000 (SF3) TM-P017. Median Age: 2000 Source: American FactFinder Thematic Mapping
The basic components of demographic change: Components of Change: births, deaths, migration Example: Population 2000 = Population1990 + Births - Deaths + Inmigration - Outmigration Or Pt+10 = Pt+ B - D + IN - OUT Often you only know “net migration”, so this becomes Pt+10 = Pt+ B - D + Net Migration You can turn this formula around to solve for Net Migration: Net Migration = (Pt+10 - Pt)- (B - D) { { Population change Natural increase
Example: If starting Population Pt = 100,000 Ending population Pt+10 = 150,000 Births in time period B = 30,000 Deaths D = 20,000 Then... Net Migration = (Pt+10 - Pt)- (B - D) Net Migration = (150,000 - 100,000)- (30,000 - 20,000) = 50,000 - 10,000 = 40,000
Panel data is the ideal data for migration studies: (following the same people over time)
Panel data is the ideal data for migration studies: (following the same people over time) Unfortunately, however, we don’t often have panel data. From the U.S. Census form, there are two key questions of interest for migration studies: 1) Where were you born? 2) Where did you live 5 years ago? (not a great measure of migration over one’s lifetime, but a start)
1) Where were you born? 2) Where did you live 5 years ago?
1) Where were you born? Source: US CENSUS American FactFinder
2) Where did you live 5 years ago? Source: US CENSUS American FactFinder