Statistical Analysis
For general methods resources, visit the Methods page. For a list of possible data sources (quantitative and qualitative) and advice on data collection, visit the Data page. For resources on collecting and coding qualitative data, visit the Qualitative Methods page. For advice on doing presentations and writing for public audiences, visit the Writing and Presentations page.
Data collection
SAGE Research Methods (books, articles, references, videos; VCU has a subscription to this service, so visit the site via these library links)
Statistics
General resources
DataCamp (online data science courses)
SAGE: Which Stats Test? (wizard to determine which statistical test to use when analyzing data)
Stat Trek (statistics tutorials)
UCLA Institute for Digital Research and Education (resources for teaching and learning statistics): annotated output | data analysis examples | faqs | textbook examples | which statistical test?
Topics
Hypothesis testing: BC Open Textbooks
Bivariate/multivariate analysis of categorical variables
Chi-square: Stat Trek
Bivariate/multivariate analysis with categorical IV and continuous DV
Bivariate/multivariate analysis of continuous variables
Other topics
Fixed-effects models: SAGE (log in via VCU Libraries)
Matching: Matching Methods (Duke)
SPSS
General resources
Kent State SPSS Tutorials | recoding variables | crosstabs | chi-square | correlation | ANOVA
Other SPSS courses: Atomic Learning | LinkedIn Learning (access through VCU) | Lynda.com | YouTube (search for specific SPSS procedures)
SPSS 28 Brief Guide (sample files in Windows version: Program Files > IBM > SPSS Statistics > Samples > English ) | SPSS cheat sheet
Installing SPSS
You can either install SPSS on your computer or use it via VCU's App2Go cloud server. We highly recommend that you install it on your computer because students have experienced performance issues and problems locating files when they use the App2Go server.
To install SPSS on your computer, follow the instructions below. If installing SPSS on a department-owned laptop, make sure to read the instructions specific to departmental laptops first.
Go to http://www.ts.vcu.edu/software-center/data-analysis/spss/.
Click on Download SPSS.
Under step #2 ("registration and download," NOT step #4, "install"), click on the link that says either SPSS XX - Windows or SPSS XX - Mac, depending on your system and your preference for a version of the software. (For Dr. Chen's classes, select SPSS 28 - Windows or SPSS 28 - Mac. If your computer is too old to run this version, you may need to install an older version. Click on the link for system requirements for more details.) If you haven’t already, you may need to log in using your VCU eID at this point. IMPORTANT NOTE: Sometimes VCU's software page will give you an "Internal error" page when you click on the SPSS link. Click on Back in your browser and then click on the same SPSS link a second time. It should work. We have alerted VCU IT to this issue.
Check all the checkboxes at the bottom of the page. For the Installation Location, select Computer(s) owned by me if you are installing SPSS on your personal computer, or Computer(s) owned by VCU if you are installing SPSS on a VCU computer (i.e., a departmental laptop or desktop). Click on Continue.
Click on the download link that will appear on the very bottom of the page. The file should begin downloading. Wait until the installation file has finished downloading. It is a large file and may take some time.
Your VCU email account should receive an email from softwarelic@vcu.edu with an authorization code. (Check your spam filter if you don’t see it.) Click on the link in the email for instructions on how to install SPSS on your specific kind of computer. (Honestly, you don't really need to follow these instructions if you are comfortable with computers; just choose the default installation options.) You can also find the instructions by going back to the earlier page with step #4 "install" (i.e., from the first page, click on Download SPSS) and clicking on the instructions link for your particular version of SPSS and your particular operating system. If you are installing an earlier version of SPSS, click on the instructions link for that version instead.
When you run SPSS, you will get a notice that "no license exists." Click on Launch License Wizard. Another program will run. Click on Next at the bottom. Choose Authorized user license (I purchased a single copy of the product). Click on Next at the bottom.
Enter the authorization code you received via email into the text box that says Enter Code. After entering it, click on Add. Then click on Next at the bottom. Your license should be renewed. Click on Next again and click on Finish at the bottom to close the license wizard. SPSS will ask you to restart the program, which you should do.
Once you have completed the licensing, you can now use the program. If the program isn’t running the way it should, it may be because you did not license the software correctly; go back to the earlier steps and try again.
Renewing your SPSS license
To renew the license for SPSS on your computer, follow the instructions below (note that the instructions are exactly the same as for installing SPSS, as described above, but you obviously do not need to download the software). If you are renewing the SPSS license on a department-owned laptop, make sure to read the instructions specific to departmental laptops first.
Go to http://www.ts.vcu.edu/software-center/data-analysis/spss/.
Click on Download SPSS.
Under step #2 ("registration and download," NOT step #4, "install"), click on the link that says either SPSS XX - Windows or SPSS XX - Mac, depending on your system. Replace the "XX" with whatever is the version number installed on your computer (e.g., SPSS 28). If you haven’t already, you may need to log into your VCU account at this point.
Check all the checkboxes at the bottom of the page. For the Installation Location, select Computer(s) owned by me if you are installing SPSS on your personal computer, or Computer(s) owned by VCU if you are installing SPSS on a VCU computer (i.e., a departmental laptop or desktop). Click on Continue.
Your VCU email account should receive an email from softwarelic@vcu.edu with an authorization code. (Check your spam filter if you don’t see it.)
When you run SPSS, you will get a notice that "no license exists." Click on Launch License Wizard. Another program will run. Click on Next at the bottom. Choose Authorized user license (I purchased a single copy of the product). Click on Next at the bottom.
Enter the authorization code you received via email into the text box that says Enter Code. After entering it, click on Add. Then click on Next at the bottom. Your license should be renewed. Click on Next again and click on Finish at the bottom to close the license wizard. SPSS will ask you to restart the program, which you should do.
Once you have completed the licensing, you can now use the program. If the program isn’t running the way it should, it may be because you did not license the software correctly; go back to the earlier steps and try again.
Opening a dataset
The SPSS Brief Guide (linked above) walks you through the process of opening a dataset, but here is a summary with of those instructions some additional points to consider. If your dataset is in the normal SPSS Statistics file format (*.sav), then you should be able to: (1) double-click on the file to open it; or (2) launch SPSS and choose the Open another file option under the Recent Files heading on the left of the intro window; or (3) from the Data Editor or Output windows, choose the File > Open > Data option.
Sometimes, you might come across a file in an ASCII (text) format (.txt, .dat, .csv, .tab) or a portable file format (.por), which are both more universal file formats readable by other programs besides SPSS. To open these files, choose either option (2) or (3) above. In the window that appears, change the Files of Type drop-down menu at the bottom from SPSS Statistics (*.sav, *.zsav) to either Text (*.txt, *.dat, *.csv, *.tab) or Portable (*.por). Then find the folder with your data file. Choose it. If you don't see a file, it may be because you didn’t select the right Files of type option, so double-check that you did. Open the file once you find it.
There are additional instructions in Chapter 2 of the SPSS Statistics Brief Guide (linked above) for opening and converting datasets that are text or Excel files and stored in other file formats.
SPSS walkthrough with the General Social Survey
Go to the General Social Survey page. Information about the survey's methodology can be found on the FAQ page linked at the bottom. Note the discussion of the sample (Which population did the GSS target?) and appropriate weights to use (Do I need to use weights when analyzing GSS data?).
To download the 2018 GSS data, go to the Get the Data link in the top menu. Click on SPSS. Under Download Individual Year Data Sets, click on 2018. The compressed (zipped) file will be downloaded to your computer. Extract it. It should give you a SPSS data file called GSS2018.sav. Open it up in SPSS by either double-clicking on it or following the instructions above for Opening a dataset.
To download the 2018 GSS questionnaire, go to the Get Documentation link in the top menu. In the sidebar on the right-hand side of the screen, click on GSS Questionnaires. Click on 2018 Questionnaires. Under English Questionnaires, you can choose between three different versions of the questionnaire, called "ballots." (The GSS has a split-ballot design, whereby each respondent is randomly assigned a particular version of the questionnaire, with different topics covered in some sections of the survey interview.) Click on the ballot you want to use, and you will download the PDF of the questionnaire.
In the SPSS cheat sheet, follow the instructions for Using weights. The variable to use for the GSS is WTSSALL.
In the SPSS cheat sheet, follow the instructions for Univariate Statistics > Frequency Tables. You can choose any categorical variable for your analysis (e.g., NATENVIY). Note that certain response categories are listed as missing variables, which means they are excluded from your analysis; see the Flagging missing values instructions in the cheat sheet for more information.
In the SPSS cheat sheet, follow the instructions for Univariate Statistics > Bar Charts, using the same variable that you used in the previous step. Follow the instructions there regarding copying and pasting the table you generated into a word processor program like Microsoft Word.
In the SPSS cheat sheet, follow the instructions for Saving output or dataset. Definitely save your output file. Save your dataset if you wish to continue to apply the same weights the next time you conduct your analysis; otherwise, you will need to repeat this step every time you use SPSS.
In the SPSS cheat sheet, follow the instructions for Univariate Statistics > Other Descriptive Statistics Tables. You can choose any continuous variable for your analysis (e.g., AGE). Note that continuous variables will have a ruler icon next to them when you are viewing variables.
In the SPSS cheat sheet, follow the instructions for Univariate Statistics > Histograms, using the same variable that you used in the previous step. As noted in the instructions, it is possible to change the binning options to make a histogram with the degree of precision you wish.
In the SPSS cheat sheet, follow the instructions for Bivariate Statistics > Crosstabs. You can choose any two categorical variables for your analysis (e.g., SEX as your IV, SPKCOM as your DV). Remember that the choice of whether to percentage by columns or rows will dramatically change the interpretation of your results. Make sure to generate the chi-square table as described in the instructions; note that the assumptions of the chi-square test must hold for your results to be valid (see the lecture slides).
In the SPSS cheat sheet, follow the instructions for Bivariate Statistics > Clustered Bar Charts, using the same variables that you used in the previous step.
If one of your variables has so many response categories that the chi-square test's assumptions do not hold (or if you just want to make your data easier to present), you can merge response categories in your data by recoding the data. In the SPSS cheat sheet, follow the instructions for Recoding variables. For example, you could recode the RACECEN1 variable into a RACECEN1_recode variable with just 3 racial/ethnicity response categories rather than 16. In the Old and New Variables pane, you would set the old Value of 1 to the new Value of 1 (keeping white respondents as is), the old Value of 2 to the new Value of 2 (keeping African American respondent as is), the Range of 3 through 16 to the new Value of 3 (putting all other races/ethnicities into a single response category), and All other values on the left-hand side to Copy old value(s) on the right-hand side (keeping the missing values as is). After doing the recoding, you will need to create value labels to match what was previously listed in the original RACECEN1 variable (except for your new response category, 3, which should be relabeled as "Other races/ethnicities" or something similar). Likewise, you should set the 0, 98, and 99 values in the recoded variable to be flagged as missing data, following how they were set up in the original RACECEN1 variable (see the Flagging missing values instructions in the cheat sheet).
Publicly available datasets
For more publicly available datasets, visit the Data page.
General Social Survey (GSS): http://www3.norc.org/GSS+Website
U.S. Census Bureau: http://www.census.gov
Inter-university Consortium for Political and Social Research (ICPSR): http://www.icpsr.umich.edu/icpsrweb/ICPSR/
ICPSR is an extensive social science data archive containing literally thousands of data sets. VCU is a member institution, and students have free access to the data. To create your personal account, you need to be signed into the VCU system (e.g., using an on-campus computer that is networked or signed into myVCU remotely). Create an account by clicking "Login/Create Account" on the top left of the home page and follow the instructions there.
Software for download or online use
SPSS: install on your computer or access via VCU's App2Go server (please review instructions above first)
Stata: access via VCU App2Go server
RStudio (graphical interface for R)