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Tableau is one of the powerful visualization tools preferred by many analysts. Tableau is a popular and widely used business intelligence and data visualization tool. It enables users to connect to and analyze data from various sources, and create interactive dashboards, reports, and visualizations that can be shared with others.
Tableau offers a variety of charts to visualize data. The most commonly used charts are
Bar charts - Used to visualize categorical data with the length or height of bars proportional to the values
Line charts - Typically used to depict data over time
Pie charts - Used to visualize part to whole relationships
Map charts - Commonly used to highlight geographical trends
Scatter plots - Used to visualize the relationship between two measures.
WHAT ARE BULLET GRAPHS?
Bullet graphs are one of the easy graphs to visualize for someone who is starting to learn data visualization and analytics. A bullet graph typically depicts the progress of a measure against a set target. It is a form of a bar chart and can be used in various scenarios where there is a need to compare current values against a forecasted value.
A bullet graph is a bar marked with extra encodings to show progress towards a goal or performance against a reference line. Each bar focuses the user on one measure, bringing in more visual elements to provide additional detail. The bullet graph depicts a single primary measure. It includes measures from other fields to enhance the graphical display for analysis. Bullet graphs, being a form of bar chart, start at zero to support visual interpretation of the data.
The bullet graph is not good for analyzing change-over-time, part-to-whole, flow, or distribution. They are best used for making comparisons. Bullet graphs are most often used to compare forecasts to actual numbers:
Business analysts check if teams or departments are on track to meet their goals.
Healthcare systems use them to gauge capacity at specific locations.
Nonprofits measure progress towards fundraising goals.
In Tableau one can create a Bullet graph with 2 measures and 0 or more dimensions.
Let's use the sample superstore data set and create a bullet graph to depict how each category is performing against a target sales. So here, we are going to be using one dimension (Category) and 2 measures (Sub category sales and target sales).
Step 1:
Because our dataset does not have a 'Target Sales' field, lets create a custom field. I am creating a new field named 'TargetSales' which has the value 750,000. This means all the categories are expected to achieve a target of $750,000. Let's create a bullet graph to see how each category is performing against this target.
Step 2:
Let us create a bar chart of Category wise Sales by dragging and dropping 'Category' into Rows and 'Sales' into Columns. By default, Tableau uses Aggregated Measures and so we get the sum of Sales over the years for each category.
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Step 3:
Now let us add our second measure, 'TargetSales' into columns. This gives another bar chart of Categorywise Target (which in our case is fixed as 750000).
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Step 4:
Now that we have 2 measures and 1 dimension, we can use the 'Show me' card and select 'Bullet graphs'.
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Step 5:
We see that the generated bullet graph shows the category wise sales and targetsales. The horizontal bar represents the target sales and the vertical line represents the sales of each category. It will make for a better understanding if the two fields were swapped. We would like the horizontal bar to represent the sales and the vertical line to represent the target sales. This can be achieved by right clicking on the Y-axis and choosing 'Swap Reference Line Fields'.
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Now we see that the representation has changed as we wanted. Here we see that the categories 'Furniture' and 'Office Supplies' are yet to reach the target sales whereas the category 'Technology' has exceeded the target.
Step 6:
The gray bar around the horizontal bar by default shows the 60 and 80% of the target values. These values can be changed using the 'Edit Reference line' option.
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Now lets edit the reference line to show 50% and 75% of the values and also change the colors to get a better visualization.
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Here, the orange band represents 50% of the TargetSales and the yellow band represents 75% of the TargetSales.
So all 3 categories have reached 75% of the target, with one category exceeding the target and the other two moving towards it.
Conclusion:
Bullet graphs are best used for comparing current values against a forecasted value. But the limitations of bullet graphs are that they cannot be used for representing trend or flow or part to whole distribution.
Hope this blog would have helped you get a basic understanding of bullet graphs and how to create one using Tableau. Thanks for reading!
References: Understanding and Using Bullet Graphs | Tableau
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