Overview
Understanding the types of statistical information that is available is vital to the process of locating statistics.
There are statistics available on an enormous variety of topics. Some examples are: batting averages for major league baseball players, the rate of teen pregnancy in Chicago, the average income of a resident of Illinois.
- Statistics are gathered because someone has determined there is a need or a use for the information.
- Statistics are most often collected for internal use within a particular agency and/or for external dissemination, making them available for use by the public.
With the growth of information available on the Internet, available sources of statistics grow almost daily.
Understanding Statistics
Why are statistics created?
It is helpful to know the factors that affect the creation of statistics:
- An established need, interest, law, or reason must exist before resources will be invested in collecting, analyzing, and publishing the data.
- Financial factors often drive the collection of statistical information. An organization may need information to help them make money, save money, or spend money in the best way possible.
- It must be feasible to collect data on the topic. Some demographic groups or topics may prove difficult or impossible to collect data about. Homeless people are more difficult to collect information about than homeowners, for instance.
- Usually there is more information available at the national level than at state or local levels.
- Sometimes the exact information that you seek is not available, but by modifying your query or changing your topic slightly, the data can often be found. For example, you may not be able to find how many people in Illinois play golf each year, but you might be able to find how many people in the United States play golf each year.
Sometimes assistance will be needed to find exactly what you need - remember to ask a librarian for help if you are not finding what you want!
Who cares about statistics?
Statistics are compiled by many different types of agencies and organizations:
- Federal, state and local governments
- Special interest groups
- Think tanks and policy institutes
- Private corporations
- Professional organizations and associations
- Educational institutions and independent researchers
- Religious organizations
- Political groups
- Nonprofit organizations
- Public interest groups
- Media
In looking for statistical information, it is helpful to think about who would be interested in the information. For example, the number of elementary school children enrolled in private schools is likely to be of interest to government agencies concerned with education. In fact, this statistic can be found in the U.S. Department of Education publication Digest of Education Statistics.
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What types of statistical information are available?
Statistical information can be divided into two types: data sets and compiled statistics.
While you will primarily be using compiled statistics, it is important to understand both formats of information.
What are data sets?
- Data sets are data in its purest form - sometimes referred to as "raw data."
- Data sets consist of information that has been collected but not yet analyzed in a meaningful way.
- Because data sets have not yet been turned into usable information in the form of summaries, charts, tables or other graphics, using a data set requires that you perform the analysis on the data yourself.
- Most data sets are very large.
- Often a codebook or manual is needed to help understand a data set.
To use data sets effectively, it is important to be aware of:
- who compiled the data,
- what methodology was used (how the data was collected), and
- when the data was collected
What are compiled statistics?
- Compiled statistics are compressed forms of information or data. In other words, data that
has been analyzed and turned into usable information. - Compiled statistics are usually presented in charts, tables, maps or other graphics.
- The column and row headings of the charts and tables, as well as any written summary or footnotes, help to provide meaning and context for the information.
- Different units of measurement may be used to help convey the information in a usable form.
To use compiled statistics effectively, it is important to be aware of:
- who compiled the statistics,
- what methodology was used (how the data was collected and analyzed),
- when the statistics were compiled and analyzed and,
- when the original data was collected. Note: a statistic may be collected as part of a data set months or years before it is analyzed.
