Survey Documentation and Analysis SDA

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Survey Documentation and Analysis (SDA)
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Presenter

• Ed Nelson
• Sociology
• CSU Fresno
• ednelson_at_csufresno.edu
• 559-278-2275

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Workshop Agenda

• Overview
• What is online analysis?
• Available SDA data sets
• Statistical procedures (Frequencies, Crosstabs,
  Regression)
• Recoding, subsetting, downloading
• Teaching resources for SDA and developing
  instructional materials

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SSRIC
Social Science Research Instructional
Councilhttp//www.ssric.org
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The Council

• Oldest CSU discipline council
• Founded in 1972
• Representatives from CSU campuses meet three
  times per year
• Negotiates with data providers for
• access to data
• Promotes use of data analysis in
• research and teaching

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The Council

• Annual student research conference
• at CSU Long Beach in 2008
• at CSU Sacramento in 2009
• Sponsors travel to ICPSR summer workshops in Ann
  Arbor, Michigan
• http//www.ssric.org/participate/icpsr_summer
• Works with Field Research
• Question credits to California Field Poll
• Selects faculty fellow

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What is Online Analysis?

• Online data analysis" refers to the ability to
  perform statistical analysis using special
  Web-based software as an alternative to
  downloading data into a standalone statistical
  package on your computer.
• The software were using is called Survey
  Documentation and Analysis (SDA), which was
  developed at the University of California,
  Berkeley.

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Alternative Statistical Packages

• You can get a complete list of available online
  statistical packages at http//statpages.org/
• Some of these include
• OpenStat
• ViSta
• Statext
• SISA

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Advantages

• Many like SDA are free dont require a site
  license
• Only require a computer with an internet
  connection
• Some like SDA are easy to learn
• Can show students how to use some of them in 30
  minutes or less

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Disadvantages

• Some online statistical packages (certainly not
  all) are limited in what they can do
  statistically
• Documentation is not very good for some
• Some (like SDA) can only be used with data sets
  that have already been created in a format that
  can be read by that package

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Available SDA Data Sets
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SDA Data Sets

• While SDA is an extremely easy statistical
  package to learn to use, its difficult to create
  SDA data sets.
• You have to purchase a SDA site license to create
  a data set and then learn how to use it.
• So we typically use SDA data sets that have been
  created for us.

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Sources for SDA Data Sets

• SDA Archive located at UC Berkeley
  (http//sda.berkeley.edu/archive.htm)
• ICPSR Topical Archives (http//www.icpsr.org/cocoo
  n/ICPSR/all/archives.xml)
• Field data located at UC Berkeley
  (http//ucdata.berkeley.edu/data_record.php?recid
  3analyze)
• List of SDA data sets at CSU Long Beach
  (http//www.csulb.edu/library/eref/datasets.html)
  
• University of Denvers IDEA project
  (http//www.du.edu/idea/data.htm

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SDA Archive at UC Berkeley (http//sda.berkeley.
edu/archive.htm)

• GSS Cumulative Datafile (1972-2008 2008 is a
  preliminary version).
• ANES Cumulative Datafile (1948-2000) and ANES
  datafiles for 1996, 2000, and 2004.
• Census microdata including 2000-2003 American
  Community Surveys and 1990 and 2000 U.S. 1 PUMS
  with separate files for 2000 and 1990 California
  PUMS.

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ICPSR

• National Archive of Computerized Data on Aging
  (http//www.icpsr.umich.edu/NACDA/)
• National Archive of Criminal Justice Data
  (http//www.icpsr.umich.edu/NACJD/)
• Substance Abuse and Mental Health Data Archive
  (http//www.icpsr.umich.edu/SAMHDA/)
• International Archive of Education Data
  (http//www.icpsr.umich.edu/IAED/)

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Field Data http//ucdata.berkeley.edu/data_record
.php?recid3analyze

• Field Polls from 1956 through 2006 are available
  as publicly-accessible SDA data sets
• More recent Field Polls are available as SPSS
  data sets (through FTP) for CSU faculty, staff,
  and students.

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Other Sources of SDA Data Sets at ICPSR

• Voting Behavior The 2004 Election by Charles
  Prysby and Carmine Scavo (http//www.icpsr.umich.e
  du/SETUPS/)
• Investigating Community and Social Capital by
  Lori Weber (http//www.icpsr.umich.edu/ICSC/index.
  htm)

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Statistical Procedures
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Available Statistical Procedures

• Frequencies and crosstabulation (discussed in
  this workshop)
• Comparison of means
• Correlation matrix
• Comparison of correlations
• Multiple regression (discussed in this workshop)
• Logit/Probit regression

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Using SDA

• Select the data set
• Look at the codebook
• Decide what statistical procedure to use
• Fill in what you want to do
• Run it

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Data Set

• Were going to use the GSS 1972-2008 Cumulative
  Data File (2008 is preliminary data)
• http//sda.berkeley.edu/archive.htm
• Were going to use three variables
• SEX
• RELITEN
• PORNLAW

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Frequencies

• List the variables you want to use
• ROW SEX,RELITEN,PORNLAW
• Click on Run the Table

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Crosstabs

• Now lets use RELITEN as our independent variable
  and PORNLAW as our dependent variable to create
  two bivariate crosstabulations.
• List the variables
• ROW PORNLAW
• COLUMN RELITEN

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Crosstabulation Continued

• Options
• Percentaging column
• Statistics
• Question text
• Color coding
• Run the Table

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Your Turn

• Lets run two more bivariate crosstabs
• Independent variable SEX
• Dependent variables RELITEN and PORNLAW
• Go ahead and run these crosstabs

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What Did we Discover?

• RELITEN is strongly related to PORNLAW.
• SEX is also related to both RELITEN and PORNLAW.
• Could the relationship between RELITEN and
  PORNLAW be spurious? SEX is related to both
  RELITEN and PORNLAW and could be creating the
  relationship between RELITEN and PORNLAW.
• How do we test this possibility? Lets run a
  three-variable crosstabulation with RELITEN as
  our independent variable, PORNLAW as our
  dependent variable, and SEX as our control
  variable.

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Multivariate Crosstabulation

• List the variables
• ROW PORNLAW
• COLUMN RELITEN
• CONTROL SEX
• Options
• Percentaging column
• Statistics
• Question text
• Color coding

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Spuriousness

• Was the relationship between RELITEN and PORNLAW
  spurious due to SEX?
• How do you know?
• Does that mean that the relationship can never be
  spurious?

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Regression

• Crosstabulation is used when all the variables
  are categorical.
• What do we do when our variables are continuous
  (i.e., interval and/or ratio)?
• Regression is the answer.

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Bivariate Regression

• Lets look at the relationship between the
  respondents socioeconomic status (SEI) and the
  amount of television one watches (TVHOURS).
• List the variables
• Dependent TVHOURS
• Independent SEI
• Options
• T-Tests
• Correlation matrix
• Color coding
• Question Text

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Multivariate Regression

• Now lets add in another variable SEX
• But sex is not a continuous variable. How do we
  enter a variable like SEX into the regression
  analysis? Answer create a dummy variable.
• Dummy variables take on the values of 1 and 0.

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Creating a Dummy Variable

• SEX (d1)
• SEX is the name of the variable to want to make
  into a dummy variable
• d indicates that you want to create a dummy
  variable
• 1 indicates that the value 1 will be assigned the
  value 1. All other values will be assigned the
  value 0.
• Run the table

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Recoding, Subsetting, Downloading
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Recoding Existing VariablesExample (from GSS
Cumulative File) ATTEND (How often Respondent
attends religious services)

• ATTEND0 Never1 Less than once a year2 Once a
  year
• 3 Several times a year
• 4 Once a month
• 5 2 to 3 times a month
• 6 Nearly Every Wk
• 7 Every week
• 8 More than once a week
• 9 DK/NA (Missing)

• ATTENDR
• 1 Seldom (0 to 3)
• 2 Sometimes (4 to 5)
• 3 Often (6 to 8)
• 9 Missing (9)

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Your Turn

• Recode AGE into the following categories
• 1 18-29
• 2 30-64
• 3 65 and older
• Obtain FREQUENCIES for the result

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For More Information, See

• http//sda.berkeley.edu/HELPDOCS/helpnewv.htmreco
  de

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Compute a New Variable Example (from GSS
Cumulative File) Alienation Index

• Create measure of ALIENATION from these variables
  asked in 1978 only (all coded as 1agree,
  2disagree, other missing data)
• ALIENAT1 PEOPLE RUNNING COUNTRY DONT CARE
• ALIENAT2 RICH GET RICHER, POOR POORER
• ALIENAT3 WHAT YOU THINK DOESNT COUNT
• ALIENAT4 YOU'RE LEFT OUT OF THINGS
• ALIENAT5 POWERFUL PEOPLE TAKE ADVANTAGE OF YOU
• ALIENAT6 PEOPLE IN WASH D.C. ARE OUT OF TOUCH

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Your Turn

• Create an index of parental education (MAEDUC
  PAEDUC)/2

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For More Information, See

• http//sda.berkeley.edu/HELPDOCS/helpnewv.htmcomp
  ute

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Subsetting and Downloading

• Example create and download a subset of the GSS
  cumulative file, selecting only cases from 2008,
  all Case Identification variables and some
  Personal and Family Information variables
  (MARITAL, AGEWED, DIVORCE, WIDOWED).
• At end of each intermediate step, click on
  Continue button.

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SPSS Syntax File
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Creating an SPSS system file

• Run SPSS (syntax) file against data (ASCII) file.
• For more information, see
• http//www.ssric.org/data/icpsr_direct (scroll
  down)
• http//www.ssric.org/data/icpsr_direct (scroll to
  Syntax Files)
• http//www.icpsr.com/cocoon/ICPSR/FAQ/0062.xml
• http//web.pdx.edu/stipakb/download/Data/SDA_data
  _to_SPSS.pdf (portions outdated)

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File Directory
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Your Turn

• Subset and download your own custom GSS SPSS
  system file.

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Sample Instructional ApplicationsCrosstabs With
a Control Variable
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Example 1

• GSS Cumulative File (selecting 2002 and 2004
  only)
• Crosstab Voting in 2000 election (VOTE00) by
  computer usage (COMPUSE).
• Repeat, but with a control for respondents
  education level (DEGREE).

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Example 2

• ANES 2004 Study
• Instructors note In addition to using this
  example in teaching use of control variables, I
  also use it in teaching about reactivity in
  interviewing.
• Run frequency distribution for V5205 (Working
  mother can have warm relationship with kids).
• Crosstab V5205 with V1109a (Respondent gender).
  Weight by Post-election weight
• Repeat, but use V4103 (Interviewer gender) as
  independent variable
• Run frequency distribution for V4103
• Repeat 1 with a control for V4103
• Repeat 2 with a control for V1109a

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Teaching Resources for SDAand Developing
Instructional Materials
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ICPSR Web-Based Instructional Materialshttp//www
.icpsr.umich.edu/ICPSR/training/index.htmlinstruc
tional
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Investigating Community Social
Capitalhttp//www.icpsr.umich.edu/ICSC/index.html

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Voting Behavior the 2004 Electionhttp//www.icps
r.umich.edu/SETUPS/index.html