OVERVIEW

When you are to gather or construct a data table, there are several dimensions to consider:

1. time (single point in time, comparative statics, time-series)

2. space (geographic location:  e.g., city, county, MSA, state, country)

3. unit of analysis (e.g., person, household)

4. variables (e.g., annual income, age, occupation)

Also: what comparative cases (if any) will you use?

Some common data problems:

1. What to do when the various variables are from different years (e.g, population from 1990, but income from 1989, etc.)
2. What to do with missing data.
3. What to do with categories not adding to 100%. (rounding error? missing data? double counting? e.g., with Hispanic wrongly added to race.)
4. How to deal with suppressed data.
5. Interpolation and extrapolation.
   

exploratory-inductive:  But sometimes serendipity leads to unexpected data.
 
 

Sample vs. Full Count (Census)
sample size - N
population size - M
sampling fraction = N/M
normally we assume that N/M -> 0 (that is, one is sampling a very small fraction of the population)
 
 

Data Sources (and Citations)

1. paper

2. electronic based on a paper published version

3. electronic with no paper published source

(also:  data tapes)

1.  Web browser (to view this document)

2.  web page composer /html editor (to create this document)

3.  FTP (to download and upload this page to my ifs space so that it is available on the web);  One MAC version is Fetch.

4.  Excel -- to analyze downloaded data (or use SPSS, SAS, Systat, etc.)

5.  Adobe Acrobat (to read formatted .pdf files)
 
 

Definitions and Historical Context

Note the connections of statistics to statecraft (common linguistic root) and to counting citizens, taxation, property.

census
OED, 2nd ed.

census se.nss, sb. [L. census registering of Roman citizens and their property, registered property, wealth, f. censere to rate, assess, estimate. ]

1. The registration of citizens and their property in ancient Rome for purposes of taxation.

2. Applied to certain taxes, esp. a capitation or poll-tax. Obs.

3.

a. An official enumeration of the population of a country or district, with various statistics relating to them. Also attrib.

A census of the population has been taken every tenth year since 1790 in the United States of America, since 1791 in France, and since 1801 in Great Britain. In Ireland the earliest census was in
1813, since which it has been taken simultaneously with that of Great Britain.

b. attrib., as in census return,

-table,

-taker; census-paper, a paper left at each house, to be filled up with the names, ages, etc., of the inmates, and returned to the enumerators on the day of taking the census.

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ENCYCLOPAEDIA BRITANNICA
http://www.britannica.com
 

  census

  an enumeration of people, houses, firms, or other important items in a country or
  region at a particular time. Used alone, the term usually refers to a population
  census--the type to be described in this article. However, many countries take
  censuses of housing, manufacturing, and agriculture.
 
 
 

-----

statistic
OED, 2nd ed.

statistic stati.stik, a. and sb. [ad. G. statistik sb. statistisch adj., Fr. statistique adj. and fem. sb., ad. mod.L. statisticus, f. *statista (Ital. statista) statist. Cf. Ital. statistico adj.,
statistica sb., Sp., Pg. estadÌstico adj., estadÌstica sb. The earliest known occurrence of the word seems to be in the title of the satirical work Microscopium Statisticum, by `Helenus Politanus', Frankfort (?), 1672. Here the sense is prob. `pertaining to statists or to statecraft' (cf. statistical a. 1). The earliest use of the adj. in anything resembling its present meaning is found in mod.L. statisticum collegium, said to have been used by Martin Schmeizel (professor at Jena, died 1747) for a course of lectures on the constitutions, resources, and policy of the various States of the world. The G. statistik was used as a name for this department of knowledge by G. Achenwall in his Vorbereitung zur Staatswissenschaft (1748); the context shows that he did not regard the term as novel. The Fr. statistique sb. is cited by LittrÈ from Bachaumont (died 1771); Fr. writers of the 18th c. refer to Achenwall as having brought the word into use. The sense-development of the word may have been influenced by the notion that it was a direct derivative of L; status state sb. ]

B. sb.

1.

a. = statistics 1. rare.
 

b. A quantitative fact or statement.
 

c. Statistics. Any of the numerical characteristics of a sample (as opposed to one of the population from which it is drawn). Cf. parameter 2 f.
 

2. = statistician.
 

-------
sample

sample s.mp'l, , sb. Forms: 4 sampel, saumpel, -pul, -ple, saunpil, 4-5 saumpil, 4-6 sampill, saumple, 5 sampil(le, sampull, saumpyl, 4- sample. [ME. sample, aphetic f. essample: see
example sb. ]

1. A fact, incident, story, or suppositious case, which serves to illustrate, confirm, or render credible some proposition or statement. (Cf. example sb. 1.) Obs.

2.

a. A relatively small quantity of material, or an individual object, from which the quality of the mass, group, species, etc. which it represents may be inferred; a specimen. Now chiefly Comm., a
small quantity of some commodity, presented or shown to customers as a specimen of the goods offered for sale. (An individual article offered as a specimen of goods sold by number and not by
weight or measure is now more commonly called a pattern.)
 

b. of immaterial things.

c. A specimen taken for scientific testing or analysis.
 

d. Statistics. A portion drawn from a population, the study of which is intended to lead to statistical estimates of the attributes of the whole population.
 

The term "census" has at least three common uses:

1.  as a type of count:  a full count (at least in theory) rather than a sample

2.  as a data set:  the actual count of the U.S. population every ten years.   Hence Decennial censuses (every 10 years - 1980, 1990, 2000, etc.)

3.  as a government agency:  the government agency that administers this count (the Bureau of the Census, which is under the Department of Commerce).  Note:  the decennial census is but one of MANY sets of data that the agency collects.
 
 
 

The U.S. Constitution provides for a census of the population every 10 years, primarily to establish a basis for apportionment of members of the House of Representatives among the States. For over a century after the first census in 1790, the census organization was a temporary one, created only for each decennial census. In 1902, the Bureau of the Census was established as a permanent Federal agency, responsible for enumerating the population and also for compiling statistics on other subjects. Historically the census of population has been a complete count. That is, an attempt is made to account for every person, for each person's residence, and for other characteristics (sex, age, family relationships, etc.). Since the 1940 census, in addition to the complete count information, some data have been obtained from representative samples of the population. In the 1990 census, variable sampling rates were employed. For most of the country, 1 in every 6 households (about 17 percent) received the long form or sample questionnaire; in governmental units estimated to have fewer than 2,500 inhabitants, every other household (50 percent) received the sample questionnaire to enhance the reliability of sample data for small areas. Exact agreement is not to be expected between sample data and the complete census count. Sample data may be used with confidence where large numbers are involved and assumed to indicate trends and relationships where small numbers are involved.

Census data presented here have not been adjusted for underenumeration. Results from the evaluation program for the 1990 census indicate that the overall national undercount was between 1 and 2 percent the estimate from the Post Enumeration Survey (PES) was 1.6 percent and the estimate from Demographic Analysis (DA) was 1.8 percent. Both the PES and DA estimates show disproportionately high undercounts for some demographic groups. For example, the PES estimates of percent net undercount for Blacks (4.4 percent), Hispanics (5.0 percent), and American Indians (4.5 percent) were higher than the estimated undercount of nonHispanic whites (0.7 percent). Historical DA estimates demonstrate that the overall undercount rate in the census has declined significantly over the past 50 years (from an estimated 5.4 percent in 1940 to 1.8 percent in 1990), yet the undercount of Blacks has remained disproportionately high.

link:    The 2000 U.S. Census
 
 

Where is each person counted? ( US Census language reproduced below with web sources ...)

2000

1990

The 2000 Census Residence Rules "Planners of the first U.S. decennial census in 1790 established the concept of "usual residence" as the main principle in determining where people were to be counted. This concept has been followed in all subsequent censuses and is the guiding principle for Census 2000. Usual residence has been defined as the place where the person lives and sleeps most of the time. This place is not necessarily the same as the person's voting residence or legal residence. Also, noncitizens who are living in the United States are included, regardless of their immigration status." FOREIGN CITIZENS "Citizens of foreign countries who have established a household or are part of an established household in the U.S. while working or studying, including family members with them - Counted at the household. Citizens of foreign countries who are living in the U.S. at embassies, ministries, legations, or consulates - Counted at the embassy, etc. Citizens of foreign countries temporarily traveling or visiting in the U.S. - Not included in the census." STUDENTS Boarding school students - Counted at their parental home rather than at the boarding school. College students living away from home while attending college - Counted where they are living at college. College students living at their parental home while attending college - Counted at their parental home.

For the 1990 Census: "Each person included in the census was to be counted at his or her usual residence--the place where he or she lives and sleeps most of the time or the place where the person considers to be his or her usual home. If a person had no usual residence, the person was to be counted where he or she was staying on April 1, 1990.   Persons temporarily away from their usual residence, whether in the United States or overseas, on a vacation or on a business trip, were counted at their usual residence. Persons who occupied more than one residence during the year were counted at the one they considered to be their usual residence. Persons who moved on or near Census Day were counted at the place they considered to be their usual residence." How about students? "Persons Away at School--   College students were counted as residents of the area in which they were living while attending college, as they have been since the 1950 census. Children in boarding schools below the college level were counted at their parental home" APPENDIX D. Collection and Processing Procedures

Two Types of Census Forms
 

questionnaire type	who received the questionnaire	2000 - Format of Compiled Census Data (Summary File)	1990 - Format of Compiled Census Data (Summary Tape File)
long form	a sample (either 1/6 or 1/2 or 1/8 of hhds. receive this form, depending on population size of location):  overall:  1-in-6.    see documentation on sampling rates.	SF3	STF3
short form	full count (every hhd. receives this form)	SF1	STF1

 

In between the 10 Year Census -- How are population estimates made?

Current Population Survey (CPS)
This is a monthly nationwide survey of a scientifically selected sample representing the noninstitutional civilian population. The sample is located in 754 areas comprising 2,121 counties, independent cities, and minor civil divisions with coverage in every State and the District of Columbia and is subject to sampling error. At the present time, about 50,000 occupied households are eligible for interview every month; of these between 4 and 5 percent are, for various reasons, unavailable for interview.

While the primary purpose of the CPS is to obtain monthly statistics on the labor force, it also serves as a vehicle for inquiries on other subjects. Using CPS data, the Bureau issues a series of publications under the general title of Current Population Reports, which cover population characteristics (P20), consumer income (P60), special studies (P23), and other topics.
 

Hispanic (many be of any racial category - so don't add with racial categories, since it cuts across racial categories)
see US Census definition
 
 

A Hierarchy of Census Areas (from the 1990 Census): from BIG to small

see a pdf version of this hierarchy
 

1	Nation (US)
4	Regions (e.g., Midwest)
9	Divisions (e.g., East North Central)
57	States and Statistically Equivalent Entities (e.g., Michigan)
3,248	Counties and Statistically Equivalent Entities (e.g., Washtenaw)
60,228	County Subdivisions and Places (e.g., Ann Arbor)
576	American Indian and Alaska Native Areas
62,276	Census Tracts and Block Numbering Areas (BNAs)
229,192	Block Groups (BGs)
7,017,427	Blocks

What are blocks?
"Census blocks are small areas bounded on all sides by visible
features such as streets, roads, streams, and railroad tracks, and by
invisible boundaries such as city, town, township, and county limits,
property lines, and short, imaginary extensions of streets and roads.
source:  technical documentation

Metropolitan Areas: Detroit as an example
 
  A Map of Lower Michigan Counties

 
 
 

35                 Detroit-Ann Arbor-Flint, MI CMSA   35 0440              Ann Arbor, MI PMSA   35 0440 26091          Lenawee County   35 0440 26093          Livingston County   35 0440 26161          Washtenaw County   35 2160              Detroit, MI PMSA   35 2160 26087          Lapeer County   35 2160 26099          Macomb County   35 2160 26115          Monroe County   35 2160 26125          Oakland County   35 2160 26147          St. Clair County   35 2160 26163          Wayne County   35 2640              Flint, MI PMSA   35 2640 26049          Genesee County

Population in the Detroit-Ann Arbor-Flint,MI CMSA and its three component MSAs,
1980 - 1994 (in thousands)

METROPOLITAN AREA	1980	1990	1991	1992	1993	1994	1980-90	1990-94
Detroit-Ann Arbor-Flint,MI CMSA	5,293	5,187	5,215	5,236	5,246	5,256	-2.0	1.3
Ann Arbor, MI PMSA	455	490	498	504	509	515	7.7	5.1
Detroit, MI PMSA	4,388	4,267	4,285	4,299	4,304	4,307	-2.8	0.9
Flint, MI PMSA	450	430	432	432	433	433	-4.4	0.7

GUIDE TO FIPS CODES:

(Note: FIPS = Federal Information Processing Standards) see this resource

MSA= Metropolitan Statistical Area

CMSA= Consolidated Metropolitan Statistical Area

PMSA= Primary Metropolitan Statistical Area

SS= State

CCC= County

PPPPP= Place (city/town)
 
 
 

Type of Metropolitan Area		Number	Example
MSA (metropolitan statistical area)	stand alone metro area (a county or counties)	268	(e.g., Lansing-East Lansing, MI MSA)
CMSA (consolidated MSA)	a very large metro area, consisting of a collection of PMSAs	21	(e.g., Detroit-Ann Arbor-Flint, MI CMSA)
PMSA (primary MSA)	a subset of CMSAs	73	(e.g., Ann Arbor, MI PMSA)

New York CMSA has 15 PMSAs

LA CMSA has four (albeit big ones)

Detroit CMSA has three: Ann Arbor, Detroit, and Flint.

MA (Metropolitan Area) The MA classification is a statistical standard developed for use by Federal agencies in the production, analysis, and publication of data on MAs. The MAs are designated by the Office of Management and Budget. Metropolitan Areas can be classified as a Metropolitan Statistical Area (MSA) or as a Consolidated Metropolitan Statistical Area (CMSA), that is a MA divided into Primary Metropolitan Statistical Areas (PMSAs.) See also MSA/CMSA/PMSA.
 

PMSA (Primary Metropolitan Statistical Area) An area defined by the Office of Management and Budget as a Federal statistical standard, comprised of one or more counties (county subdivisions in New England), within a metropolitan area, having a population of 1,000,000 or more. When PMSAs are established, the larger area of which they are component parts is designated a Consolidated Metropolitan Statistical Area.
 
 

CMSA (Consolidated Metropolitan Statistical Area) An area defined by the Office of Management and Budget as a Federal statistical standard. In metropolitan areas where Primary Metropolitan Statistical Areas (PMSAs) are defined, the larger area of which the PMSAs are components is designated a CMSA.
 
 
 

MSA (Metropolitan Statistical Area) An area defined by the Office of Management and Budget as a Federal statistical standard. An area qualifies for recognition as an MSA if it includes a city of at least 50,000 population or an urbanized area of at least 50,000 with a total metropolitan area population of at least 100,000. See also (MA).
 
 

NECMA (New England County Metropolitan Area) A county-based equivalent to the official metropolitan areas in the six New England States, where the standard components are county subdivisions (cities and towns) instead of counties as in other states.
 
 

For descriptive details and a listing of titles and components of MA's, see Appendix II.
 
 

Metropolitan Areas (MA's)
The general concept of a metropolitan area is one of a core area containing a large population nucleus, together with adjacent communities that have a high degree of social and economic integration with that core.

Metropolitan statistical areas (MSA's),

consolidated metropolitan statistical areas (CMSA's),

and primary metropolitan statistical areas (PMSA's)

are defined by the Office of Management and Budget (OMB) as a standard for Federal agencies in the preparation and publication of statistics relating to metropolitan areas.

The entire territory of the United States is classified as metropolitan (inside MSA's or CMSA' -- PMSA's are components of CMSA's) or nonmetropolitan (outside MSA's or CMSA's).
 
 

MSA's, CMSA's, and PMSA's are defined in terms of entire counties except in New England, where the definitions are in terms of cities and towns. The OMB also defines New England County Metropolitan Areas (NECMA's) which are countybased alternatives to the MSA's and CMSA's in the six New England States. From time to time, new MA's are created and the boundaries of others change. As a result, data for MA's over time may not be comparable and the analysis of historical trends must be made cautiously. For descriptive details and a listing of titles and components of MA's, see Appendix II.

How to access the 2000 Census Data:

for an overview, see Comparison of 2000 Census Delivery Vehicles, UM Documents Center

two of many options:

1. How did the Census handle non-English speakers? The Census did provide Census forms in languages other than English. Please see this link.
2. How were migrants from Puerto Rico to the 50 US States classified? As "native" but "born outside the United States". There are two broad categories: "Native" and "Foreign Born". "Native" is divided into "born in the United States" and "born outside the United States" (the latter including "Puerto Rico", "US island Areas" and "Born abroad of American Parents"). "Foreign born" is divided into "Naturalized citizen" and "Not a citizen".
3. Where are citizens living abroad counted? It depends on employment status and whether you are in the military or not. For a detailed discussion, see "Residence Rules" for the 2000 Census. To quote this source:
   "U.S. CITIZENS ABROAD
   U.S. citizens employed overseas as civilians by the U.S. Government, including family members with them - Counted as part of the U.S. overseas population and not as part of the U.S. resident population.
   U.S. citizens not employed by the U.S. Government who are working, studying, or living overseas - Not included in the census."
   (Source: U.S. Census Bureau, Population Division, Population & Housing Programs Branch Maintained By: Laura K. Yax (Population Division) Created: August 9, 1999 Last Revised: September 13, 2002 at 07:24:37 AM)