Introduction

Welcome. You are about to become an investigator, but not the familiar kind depicted in television dramas involving crime scenes with evidence such as smoking guns. Instead, your assignment is a "social science" investigation, using the evidence found in quantitative data. In fact, scholars who receive grants for their research from the prestigious U.S. National Science Foundation are referred to as "principal investigators."

Based on quantitative data used in Robert D. Putnam's book, Bowling Alone: The Collapse and Revival of American Community, the exercises on this Web site introduce you to an investigation of Putnam's claim about social change in America--that community is declining. Next, the exercises guide you in an investigation into why this is happening, whether it matters (so what), and what is to be done about it in the future. Overall, the exercises illustrate social science investigation and build your skills in data 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 used for this Web site is called Survey Documentation and Analysis (SDA), which was developed by the Computer-assisted Survey Methods Program at the University of California, Berkeley.

As you proceed with your investigation in the exercises on this Web site, you will encounter common, but often complex, statistical terms such as "level of measurement" or "contingency tables." Therefore, in addition to Putnam's book:

• First, you should consult a social science methods/statistics text as you encounter these terms. The sheer number of social science texts on methods and statistical analysis is staggering. Your instructor can suggest a good text that fits well with your particular area of study, or check out a highly accessible online book, Research Methods Knowledge Base, by William M. Trochim.

• Second, when you encounter terms next to the eye symbol, , click on the eye symbol to read an explanation and definition on Wikipedia, an online encyclopedia. Keep in mind that Wikipedia is a little different from a traditional encyclopedia because the entries can be edited by anyone on the Web. The article "Internet Encyclopaedias go Head to Head" in Nature has a useful discussion about this issue.

In order to conduct a social science investigation, you will need to develop some technical skills for data analysis, somewhat like a forensic scientist. The exercises on this site will assist you in developing these data analytic skills:

• Exercise 1
  Searching Codebooks
  Running and Interpreting Frequencies
  Producing and Interpreting Bar Charts
  Running and Interpreting Summary Statistics

• Exercise 2
  Producing and Interpreting Line Charts
  Recoding Variables

• Exercise 3
  Running and Interpreting Crosstabulations

• Exercise 4
  Running and Interpreting Correlations
  Using the Compute Command to Create New Variables
  Exporting Data into other Statistical Programs

Now, before officially beginning your investigation, you will need some background about the case to which you have been assigned.