demographic data & pop over time Flashcards
2 types of data
primary
secondary
what is primary data
- Data collected by you specifically for the purpose in mind
- Generally fresh and collected for the first time
- Collected under your control
e.g. You’re interested in the views of FSU students regarding population policies - You design a questionnaire to collect this information
examples of quantitive and qualitative primary data
- quantitive = experiments, surveys
- qualitative = focus groups, human observation, case studies
advantages of primary data
- Applicable and usable
- Accurate and reliable
- Up-to-date
- Greater control
- Addresses specific research interest
disadvantages of primary data
- Expensive
- Not immediately available
- Time consuming
what is secondary data
- Data collected by someone else
- Collected for a different purpose
- Sometimes called “exhaust data.”
- The data are being reused, usually in a different context
- e.g. You use your friend’s questionnaire of FSU students regarding population policies to investigate something different
advantages of secondary data
- Inexpensive
- Easily accessible
- Immediately available (time saving)
- Relevant
- Complements primary data
examples of secondary data external sources and administrative records
- external sources = Census, Surveys, Social Media
- administrative records = birth records, Post Office
addresses, Population Registers
disadvantages of secondary data
- May be inaccurate
- May be inconsistent
- May be inaccessible
- May be outdated
- Variations in definitions of terms
- Different units of measurement
- Inconvenient to compare
3 sources of demographic data
- Registration of vital statistics
◦ population processes of births and deaths - Census of population
◦ population, demographic structure and
characteristics - Administrative data
◦ Local population changes, geographic mobility
and migration
what is the Registration of Vital Statistics
- Primarily administrative
- Collects data on vital events (live births,
deaths, marriages, divorces, etc.) - e.g. bills of mortality - used as reminder to produce life expectancy
Registration of Vital Statistics advantages
- Continuously collected
- May provide both numerator and denominator (Infant Mortality Rate)
- Small area data are available
- Base for testing the accuracy of censuses and surveys
Registration of Vital Statistics disadvantages
- Uncertain coverage.
- Limited background information
- Time reference inconsistent with denominator
- May come from third party
- Easily disrupted by political/economic events
what is Census of population
- The term “census” = Latin word of assess
- Ancient censuses differed from modern censuses - they were largely used for taxation + military purposes
- the largest peacetime activity undertaken by the
federal government - it’s our civic responsibility to complete the Census - populations in the census = de facto population + de jure population - based on usual residence (where they sleep (U.S.,Canada, Mexico))
what is the de facto population in the census
people who are in a given territory on census day - can think of it as daytime population
what is the de jure population in the census
people who legally “belong” to a given area, regardless of whether they were there on the day of the census - can think of it as nighttime population
whats the purpose of the census
To conduct a census of population and housing and disseminate the results to the President, the States, and the American People
primary uses:
- Apportion representation among states
- Draw congressional and state legislative districts, school districts, and voting precincts
- Distribute federal dollars to states <- $400 billion per year
- Provide detailed information on the populace
- Population Benchmark for other surveys
overview of how a census is designed / how it works
- establish where people are - where are all the housing units? - satellite imagary, postal etc
- motivate people to respond
- count the population
- release census results - has to be delivered to president at end of census year
**counting housing units to then count the actual number of people
- LUCA allows people to update their addresses
what is the census day (count date)
April 1 (XXX0)= census day - always use base number for population
July 1 = midway point - use to look at population change over time
what is the long form and short form of census
- LF = 40 pages - contains all the good stuff e.g. how many toilets are in your house - this one was eventually eliminated - ACS is a replacement to this
- SF = 6 pages - essentially 10 questions about basic stuff e.g. age, sex
advantage of ACS
on-going collection so new questions can be added
- In 2015 the CB released its first internet question
data - was not a concern in 2005 - would not know important data about internet in households without the ACS
2 primary data products published by ACS
1-year + 5-year estimates
- Areas with more than 65k people, have both 1-
year and 5-year estimates
- smaller areas have to wait longer for immediate intelligence
- CB used to publish 3-year estimates, but those are discontinued
what are the ACS data products
- Census Bureau suggests comparisons between
estimates should not include overlapping years - BUT, some companies are treating the 5-
year estimates as 1-year estimates based on the
mid-points <- Not a CB recommendation
2 errors you can get in CB
- margins of error
- Net Coverage Error
3 options when dealing with the margins of error
- ignore them! - Even the CB will do this
- Use the margin of error from the CB
- calculate the MOE yourself - typically when you
combine estimates
**You can also “eyeball” the MOEs to determine if something is significantly different or not
what is the net coverage error
he difference between those who were erroneous excluded (missing people) and those who were erroneously included (counted people twice)
**pop aged 0-4 =most likely age group to be undercounted
