Guest Author - Chris Curtis
Today’s charting is simplified by Excel’s Charting tools. Older folks would refer to these charts as graphs and many will have remembered plotting graphs by hand. Now data is easily organized into Charts using Excel. Data can be displayed in 10 different categories of charts with each category offering several sub-categories. In addition to the standard charts, Excel also offers a variety of custom charts. By default, a simple bar chart is created using a data selection and the F11 key. The type of chart created by default can be changed by the user.
The most common chart is the clustered column where you might compare changes in value over a period of time. For example: You would use this type of chart to compare changes in revenues over 2 years by quarter results. Two variations of this type of chart are the Stacked Column and the 100% Stacked column that show the relationship of each data point to the whole across categories.
The bar chart is very similar to the Column Chart but is presented horizontally. Variations of the bar chart are the Stacked Bar and the 100% Stacked Bar. These charts are read and interpreted in the same way a Column Chart would be.
You would use a line chart when you want to show trends. For example: you want to look at the movement of your stock portfolio over time and compare the trends of each holding. A line chart helps to visualize the trends and gives the reader an opportunity to compare the trends between different stock holdings. Variations include stacked line and 100% stacked line as well as lines with markers or 3-D lines.
The purpose of a Pie Chart is to display data as a percentage of the whole. It gives the reader a good sense for the contributions of each element of data to the whole. Variations of the pie chart include the Exploded Pie, 3D Effects for the traditional pie and the exploded pie, the pie of pie which further segments a section of the pie, and the Stacked Bar of Pie which further segments a section of the pie.
You would use a scatter chart when you want to compare pair sets of statistical or scientific data. Suppose you wanted to look at the paired data between the number of Nascar races won and earnings. So for example, one driver earned $70,000 winning 30 races. This data would be plotted at $70,000 on the vertical axis and 30 on the horizontal axis. In this case you are dealing with statistical data and are looking for patterns within the data. Variations include the data points to be connected by smooth or straight lines with or without point markers.
Area charts plot similarly to a line chart except the area below the line is filled with color. It is useful when you want to emphasize the size and relationship of the data to the whole.
Donut Charts can be used in place of a pie chart and are designed to show the relationship of each of the data points to the whole. The benefit of a Donut Chart over that of a Pie Chart is that you can display multiple series in a donut chart.
Radar Charts are useful when you want to look at changes in values around a central point. Suppose your goal was to shrink the number of production exceptions. You implements several strategies to drive the exceptions down. You now want to compare the results in a clear picture. The Radar chart helps you to see the big picture as to how the data appears month to month over a 3 year period. The bar chart is more difficult to understand and absorb. The radar chart more clearly shows the data trend.
Surface Charts provide for a true three dimensional view of 3 sets of data. It is designed to show trends in data across two dimensions.
Bubble Charts are similar to a scatter chart in that there are two value axis and the data being used has three data points. For example: Suppose you wanted to look at your winnings at the dog track. You have tracked the number of races won, the dollars won and the % of the total purse for each date you went to the races. The # of races won would be on one axis, the dollars won would be the 2nd axis and the % of the total purse would be represented by the bubble.