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Alfredo Pareto was an Italian sociologist who suggested that "80% of all wealth in this country is owned by 20% of the people." (In our country today, the percent is closer to 90%/10%.) This supposition was further devel-oped by business and industry leaders who found that most of the quality problems were confined to a small number of machines or workers. In other words, "80% of problems come from 20% of the equipment or workforce."

The Pareto Principle is used by business and industry to work to continually improve quality -- whether it be a product or a service. Quality improvement involves tackling one issue at a time. After all, there is rarely just one cause related to a problem. By addressing the one causing the most difficulty (the 20% which are causing 80% of the problem), improvements can be made and monitored for continuous progress. Bar charts, called Pareto charts, are used to decide what steps need to be taken for quality improvement.

A Pareto chart is simply a bar chart that sorts defects, errors, and issues, in decreasing order. In doing so, it is clear which problem is causing the greatest difficulty. Pareto charts can be used to see whether strategies used to correct problems have been effective.

What does the Pareto Principle have to do with education? And, more specifically, what does it have to do with assessment? Documenting a learner's errors using Pareto charts is an interesting way for learners to see evidence of growth, especially when they are working on discrete skills. Pareto charts can also be used to document overall improvement of a class.

Let's imagine you are an English teacher. Sometimes it's difficult to articulate to learners just how their writing has improved. Pareto charts can help you and your learner note progress.

Let's say you want to know what types of conventions of English errors learners are making in order to figure out what areas to address. Begin by having each learner provide a writing sample. Analyze the mistakes that the learner makes. You can create a key so that you can code each error made. This makes it easier for the learner to see the types of errors he most typically makes. (See figure 1.)

Have each learner create a Pareto chart showing the errors. The bars should be in descending order. The bar representing the most frequent type of errors is often the one that the learner should focus on first.

After the learner has had a chance to work on a particular area (the one in which she had the most errors), do another analysis of a writing sample. Again, use the same coding. The learner again creates a Pareto chart showing the frequency of errors. The largest bar should now be different from the earlier Pareto chart. By looking at this new chart, the learner can see what area to focus on next. This new chart serves as a "pre-assessment" for the next area of focus. (See figure 2.) (Notice that the assessment involves looking at how learners are applying their new learning in the context of a writing activity rather than simply documenting the completion of pages in a text of workbook.)

If learners keep their charts in their portfolios they can clearly see how they have shown improvement over time. They are aware of what discrete skills they have learned and are able to apply in their writing. They also are getting an opportunity to see how to use math to communicate. And, they are learning a valuable tool used in business and industry.

Donna Curry is the Publications Coordinator for the EFF National Center and has done staff development training for adult educators for 10 years. She can be reached by e-mail at donnac@clinic.net