Minitab's Value Order
Controlling Order for More Meaningful Output
It's common to group data into categories that imply a specific order, such as Good, Better, Best or Beginning, Middle, End. But if they were to appear in a different order in tables and graphs (e.g., Beginning, End, Middle), it could be confusing and distract from your message. For example, suppose you are taking inventory at a clothing store and you have t-shirt sizes stored in a column in your worksheet. If you display a bar chart to represent the number of t-shirts in each size, by default, Minitab puts the bars in alphabetical order (L, M, S, XL, XS). You, of course, want the bars to appear in size order (XS, S, M, L, XL). Fortunately, with Minitab's value order feature you can easily ensure that bars appear in the correct order, resulting in a chart that is much easier to understand.
Where value order can help you
When you apply a value order to a column of text data, the information will be processed and presented in the order you specify. The value order can affect several aspects of your output.
Graphs
Graphs that present information in an unexpected order can be more difficult to interpret. For example, in the first bar chart below, weekday data in alphabetical order show no apparent pattern. After you apply a weekday value order, trends in the data are easier to detect.
Before  Bars appear in alphabetical order by default. | After  Applying a weekday value order allows you to see trends in the data over time. |
The value order of a column affects the order in which categories are plotted on many graphs, including bar charts, individual value plots, boxplots, interaction plots, and main effects plots.
Legends
A similar problem occurs with legends, which list items in the order they are plotted. A legend with items in an unexpected order can be difficult to understand. For example, consider the first pie chart below in which education levels are listed alphabetically. Setting an education value order results in a clearer presentation.
Before  The default alphabetical ordering of education level is confusing. | After  An education level value order makes the pie chart more understandable. |
Session window output tables
It is distracting to view output that is not in the correct order, as shown in the first table of product rating data below. Readers must jump around in the table in order to read information in logical order. After the correct value order has been imposed, the information is much easier to follow.
Before  It is hard to make sense of this table when categories are in an unexpected order. | After  Categories in logical order are easier to interpret. |
Try it yourself
You can apply a value order to a column in a few simple steps, without touching the actual data.
For example, suppose your company has three levels of support plans: Gold, Silver, and Bronze. The Gold plan offers the highest level of support and costs the most, the Bronze plan offers the lowest level of support and costs the least, and the Silver plan is in between Gold and Bronze. You have a column containing the support plan type for each of your customers. |  |
You want to compare the counts for each plan, so you create a bar chart. The plans appear in alphabetical order in the chart. |  |
You would like to change the value order of the Support Plan column so that Gold always appears first, followed by Silver and Bronze.
- With the Support Plan column active, right-click it and choose Column > Value Order.
- Choose User-specified order.
- Under Define an order, specify the correct order.
- Click OK.
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Now, when you create a bar chart, the plans appear in the specified order. It's easy to see that as plans get less expensive, more customers purchase them. Note that the column in the worksheet looks the same — the value order doesn't become apparent until you view the output, and it stays with the column until you change it again. |  |
Putting It to Use
Categories ordered incorrectly in graphs and tables can be confusing and may result in reports that are difficult to read. Take control of your output by imposing your own value order. Controlling value order is a simple way to ensure that your results are presented clearly and professionally.