Chapter 16: Preparing Data for Analysis

Introduction

The previous chapters described ways of collecting data. Now, we will examine how data are analyzed to produce the findings of an investigation. We will look mainly at how data from items on a questionnaire are analyzed, although the techniques described can be used to analyze most other kinds of data as well.

Data analysis consists of two related sets of activities. First, the raw data - responses to items for instance - have to be prepared for analysis. After data are organized, analyses can begin. The following three chapters describe alternative ways of analyzing data. Second, the data are then analyzed. How data are prepared for analysis, however, depends on the technique of analysis to be used. You can do analysis by hand or by computer. In hand analysis, responses to each item are counted or tallied manually. Computer analysis requires the use of a statistical analysis program, also called a software package. Today, there are a number of programs designed specifically for use in analyzing social science data.

Hand versus computer analysis

Hand analysis

For many researchers undertaking their first project, hand tallying may be the fastest and easiest way to analyze data. Conditions favoring hand analysis include:

• A small sample, less than 100 respondents;
• Relatively few variables, less than 10 or so;
• Mainly closed items, which are easy to tally;
• Simple forms of analysis and few statistical tests.

If your research design matches these conditions, hand tallying and analysis may be your best choice. On the other hand, you may want to use a computer analysis method, even with a small analysis task, in order to learn how to do this. If you do any large scale study, you certainly will want to to use a computer analysis package.

Computer analysis

For studies with larger samples, a number of variables, and a lot of analyses, hand analysis can be a tedious, slow task. This is especially true when you do a number of statistical analyses. Computer analysis eliminates these calculations, saving you a lot of time.

Using a computer has several other benefits as well. Computer-based analyses eliminate errors that almost always creep into hand tabulations, many of which are often hard to detect and correct. Also, with a computer you can use more powerful statistical tests in analyzing your data. This will strengthen your ability to draw clear, defensible conclusions from your data.

Computer analysis, however, also has its downside. A certain amount of careful work has to be done before the computer can do its magic. First, you have to design a data file to tell the computer what you are going to enter and where the data are to be stored. The data file contains the short names you will assign to each variable; the codes for the attributes of each variable you enter; and their locations in the data file for each variable and its attributes. Later in this chapter we show how this is done.   When the data are entered, the computer knows where the data for each variable is stored and can follow instructions you provide.

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