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Good Visualizations make Better Decisions

Data visualization is graphical representation of data. By using data visualization tools like chats, graphs and maps, it becomes easier to under stand the trends , outliers and patterns in data. It provides an excellent way to represent our data even to a non-technical audience without any confusion.

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What are the advantages and disadvantages of data visualization?


Our brain analysis the figures and patterns more quickly then the data present in the text format. Our eyes quickly identifies the colors and analysis it. Data visualization is a form of art to grab the user attention quickly.

Some other advantages of data visualization include:

  • Information can be easily shared.

  • Opportunities can be explored interactively.

  • Visualize patterns and relationships.


While there are many advantages, some of the disadvantages may seem less obvious. For example, when viewing a visualization with many different data points, it’s easy to make an inaccurate assumption.

Some other disadvantages include:

  • Biased or inaccurate information.

  • Correlation doesn’t always mean causation.

  • Core messages can get lost in translation.

Importance of Data Visualization:

The importance of data visualization is simple: it helps people see, interact with, and better understand data. Regardless of level of expertise, right visualizations cab bring everyone on the same page. Every STEM related industries likes to study the current trend or the data received from previous years and tries to make necessary changes in the organizations to achieve required goals / targets. There are many real life examples where data is interpreted on daily basis and decisions are taken. The professional way of visualizing data is done by Tableau. It is increasingly valuable for professionals to be able to use data to make decisions and use visuals to tell stories.

In this blog we will try to create reference lines and reference bands in Tableau to better understand the data.

Creating a Reference Lines and Reference Bands in Tableau

The same old way of analyzing data leads to same old results. To avoid this, data need to be interpreted in different ways. And better understanding of the data principals us to take better decisions or conclusions. To achieve this, we have a feature of creating Reference lines and Reference bands in Tableau.

When analyzing data, it is always obvious that the fields are often compared(referred/measured) against certain values like average sales/ average profit/ targets set or last year sales…etc. By doing this we will be trying to better understand the data and its behavior with the existing fields.

Creating a Reference Lines

Reference Lines is a most useful and graphical enhancement tool. Reference lines can be created on constant or computed values on the axis. Computed values can be based on a specified field.

In this blog I will be working on the sample superstore data to show how to create them.

The first step is to add the sample superstore data source file to Tableau Workbook and drag the orders sheet to the analytics pane.

After creating the data link, I have created a bar graph by considering segments and sum(sales) in the columns and category and subcategory in the rows.

For the graph to look more color full I have added category to colors.

By right clicking on the bottom sales axis, we will have an option of creating a reference line

By clicking add reference line, a dialogue box will open for editing the reference line parameters. It will appear as below. Select the line box, scope as per pane and labels to values.

When it comes to formatting it just have a gray line i want it to be more bright, thick and colorful,

We can also fill the color to below or above the reference line by selecting the suitable color as per the requirement.

Our bar graph after adding the reference line will be as shown below

While observing the graph for the office supplies, we can understand that only two subcategories have the maximum number of sales contributing to the maximum of the average. We can select the specific bar in the graph to show the new reference lines for specific values are created.

This feature of selecting dynamically the required values and finding the average of just those selected will be a handier tool in tableau.

That's it, we are all done. We have created a reference line and can select the required sales values to see if the sales of subcategories reached the level of Average sales.

Now let's start working on creating Reference Bands.

Creating Reference Bands

Reference Bands work in the similar way to the Reference lines. Reference lines show only one value whereas the reference band shows a range of values like minimum and maximum, and we can color the band. This is a very useful tool when we want to know the values which are lying above or below certain boundary points.

I have used the same sample superstore data to create a simple line graph. I have used (Oder date (Month) in the columns and the Sum of Profit in the Rows and the graph looks like this.

We can add the reference band in the same way we added the reference line by right clicking on the bottom of the axis line. Let's try out a different way of creating it. On the Left top corner next to the Data pane, we have an Analytics pane. The reference band which we are interested in creating is at the bottom of the analytics pane. Drag the Reference Band icon to the view and get a small dialog box open asking for the scope of the reference band.

We would like to create a reference band only for the Sum Profit. So, select the sum profit and we can see that edit reference band dialogue box automatically opening.

Tableau automatically selects the band values to Minimum and Maximum which will create a fixed band. We would like to have varying reference band. For this change the minimum value to average in the band from selection and also add the formatting to line by selecting the line and its color. We can fill the band range by choosing a color.

By clicking ok our reference band is created and the graph looks like this.

In the above graph we can observe that the average of the reference line is 5,867 and the maximum is 17885. By selecting the required months in the graph, the reference band will be calculated automatically and displayed.

Now by selecting the required data points our new average and maximum are created. we get a smaller band because of the different average and maximum values.


Data visualization by tableau is a great tool to know about your data trends and interpret the data. Reference bands and reference lines give an easy way to understand our data and can be compared to maximum / minimum/ average values. It gives a quick and easy way to know about the focus points where the next action steps are needed for a company to focus on to increase the sale/ profit.

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