## Understanding the Reports

### Pareto Charts

The Pareto chart provides facts needed for setting priorities based on the Pareto principle that 80% of problems usually stem from 20% of the causes. Pareto charts help teams focus on the small number of really important problems or causes of problems. Pareto charts organize and displays information to show the relative importance of various problems or causes of problems, and are therefore useful in establishing priorities by showing which are the most critical problems to be tackled or causes to be addressed. Comparing Pareto charts of a given situation over time can also determine whether an implemented solution reduced the relative frequency or cost of that problem or cause.

A Pareto chart is a special type of bar chart where the values being plotted are arranged in descending order. The graph is accompanied by a line graph which shows the cumulative totals of each category, left to right.

The bars are placed on the graph in descending order of frequency, which makes it easy to identify those problems that are of greatest importance or those causes that the most frequent reasons for customer complaints. The left vertical axis generally displays the frequency of occurrence (number of events), but it can also represent any other important unit of measure.   Each vertical bar represents the contribution to the total from a given "problem" area, and each vertical bar may be further broken down into color-coded parts representing the relative distribution of problems by such things as aspect (Application Failures, Connectivity, Performance, etc) or resource type (database, web service, internal execution, etc).  A cumulative line is used to add the percentages from each bar, starting at the left (highest cost or count) bar. Thus, we can see which bars contribute the most problems, and with the cumulative line, determine how much of the total problem will be fixed by addressing the highest few.

Note that there is generally a number on the x-axis of the chart with a label such as "Request Number" or "Source Number" below it. The detail table below the chart acts as a key to the meaning for each number. For example:

When to Use a Pareto Chart

• When analyzing data about the frequency of problems or causes in a process.
• When there are many problems or causes and you want to focus on the most significant.
• When analyzing broad causes by looking at their specific components.

Things to look for:

In most cases, two or three categories will tower above the others. These few categories which account for the bulk of the problem will be the high-impact points on which to focus. You can also:

• Look for a break point in the cumulative percentage line. This point occurs where the slope of the line begins to flatten out. The factors under the steepest part of the curve are the most important.
• Look for the factors that make up at least 60% of the problem.

### Pie Charts

Pie charts are divided into sectors illustrating relative magnitudes or frequencies or percents. In a pie chart, the size of each sector is proportional to the quantity it represents. Together, the sectors create a full disk.  Like with the Pareto chart, a pie chart gives an immediate visual idea of the relative impact of various problems or causes of problems, and are therefore useful in establishing priorities by showing which are the most critical problems to be tackled or causes to be addressed. Each sector is color coded to reflect the measurement described in the accompanying key.

### Tables

Most of the reports follow the initial graph with an overview  table of the data used to create the graph, with one row for each point on the x-axis, such as problem sources. The initial table is usually followed by a series of detail tables, one for each row of the overview table. Additional sub-tables may appear within each detail table.

Example:

The "Summary Performance Analysis" report displays:

• A Pareto chart of sources by number of events, with each source bar broken down by the resource type (Database, Web Service or Internal Execution).

• A table summarizing data for the sources displayed in the Pareto chart:

• An individual table for each Source row in the "Overall Performance Statistics" table is then displayed:

• A sub-table of "Top 5 Performance" events appears within each Source table:

Last update: Thursday, December 09, 2010 02:42:45 PM