According to the Pareto Principle, in many situations 80% of results come from 20% of causes or sources. A Pareto chart is specifically designed to evaluate whether process data fits this principle. It is commonly used in Six Sigma and other quality methodologies, and as part of general project management techniques, to determine the critical few priorities for a business. For instance, a business leader might use this type of chart to analyze customer survey data to determine the biggest sources of customer dissatisfaction, and then charter projects to address the top problems. Use our guide to find information about when to use a Pareto chart, how to interpret it, and even how to create one in Excel.