Combo charts (bar + line) in Tableau - Dashboard Guide

Dashboard Mode - Combo charts (bar + line)

Dashboard Goal

Understand monthly sales performance and profit trends together to see how profit changes relate to sales volume.

Sample Data

Month	Sales	Profit
January	1000	200
February	1500	300
March	1200	250
April	1700	400
May	1600	350
June	1800	450

Dashboard Components

• KPI Card: Total Sales calculated as SUM([Sales]). Result: 8800
• KPI Card: Total Profit calculated as SUM([Profit]). Result: 1950
• Combo Chart: Monthly Sales and Profit with bars showing Sales and a line showing Profit over months January to June.
• Table: Detailed monthly data showing Month, Sales, and Profit.

Dashboard Layout

+----------------------+----------------------+
|      Total Sales      |      Total Profit     |
|       (KPI Card)      |       (KPI Card)      |
+----------------------+----------------------+
|                                              |
|          Combo Chart (Bar + Line)             |
|                                              |
+----------------------------------------------+
|               Monthly Data Table              |
+----------------------------------------------+

Interactivity

A filter for Month allows selecting one or more months. When applied, the KPI cards, combo chart, and data table update to show data only for the selected months.

Self Check

If you add a filter to show only March to May, which components update and what will the Total Sales KPI show?

Answer: All components update. The Total Sales KPI will show 1200 + 1700 + 1600 = 4500.

Key Result

Dashboard showing monthly sales and profit with combo chart and KPIs for total sales and profit.

Practice

1. What is the main purpose of a combo chart in Tableau?

easy

A. To filter data based on categories

B. To create a pie chart with multiple slices

C. To show only one measure as a bar chart

D. To display two different types of data using bars and lines together

Solution

1. Step 1: Understand combo chart definition

   A combo chart combines two chart types, usually bars and lines, to show different data types together.

2. Step 2: Identify the purpose in Tableau

   In Tableau, combo charts help compare two measures visually by using bars for one and lines for another.

3. Final Answer:

   To display two different types of data using bars and lines together -> Option D

4. Quick Check:

   Combo chart = bars + lines [OK]

Hint: Combo charts mix bars and lines to compare two data types [OK]

Common Mistakes:

• Thinking combo charts show only one measure
• Confusing combo charts with pie charts
• Believing combo charts filter data

2. Which step is necessary to create a combo chart in Tableau?

easy

A. Use dual axis and set different mark types for each measure

B. Create a calculated field with IF statements

C. Apply a filter to exclude null values

D. Use a single axis with one mark type

Solution

1. Step 1: Identify how to combine bars and lines

   To combine bars and lines, Tableau requires dual axes so each measure can have its own scale and mark type.

2. Step 2: Set mark types for each axis

   After dual axis, set one axis to bar marks and the other to line marks to create the combo effect.

3. Final Answer:

   Use dual axis and set different mark types for each measure -> Option A

4. Quick Check:

   Dual axis + mark types = combo chart [OK]

Hint: Dual axis + different marks = combo chart in Tableau [OK]

Common Mistakes:

• Trying to use one axis for both bars and lines
• Confusing filters or calculations with combo chart setup
• Not setting mark types separately

3. Given a combo chart with Sales as bars and Profit Ratio as a line, what happens if axes are not synchronized?

medium

A. The chart will show an error and not render

B. The line and bars may appear misaligned, confusing interpretation

C. The bars will disappear but the line remains

D. The line will convert to bars automatically

Solution

1. Step 1: Understand axis synchronization

   When axes are not synchronized, the scales differ, causing bars and lines to not align properly.

2. Step 2: Effect on visualization

   This misalignment makes it hard to compare values visually, confusing the viewer.

3. Final Answer:

   The line and bars may appear misaligned, confusing interpretation -> Option B

4. Quick Check:

   Unsynced axes = misaligned chart [OK]

Hint: Always sync axes to align bars and lines clearly [OK]

Common Mistakes:

• Expecting an error instead of misalignment
• Thinking bars or lines disappear
• Assuming automatic mark type changes

4. You created a combo chart but the line chart is not visible. What is the most likely cause?

medium

A. The second axis is not added or dual axis is not enabled

B. The data source has no values for the line measure

C. The bar chart is overlapping the line chart due to mark size

D. The filter excludes all data points for the bar chart

Solution

1. Step 1: Check dual axis setup

   If the line is missing, often the second axis for the line measure was not added or dual axis was not enabled.

2. Step 2: Confirm mark types and axes

   Without dual axis, Tableau cannot overlay line and bar marks properly, so the line won't show.

3. Final Answer:

   The second axis is not added or dual axis is not enabled -> Option A

4. Quick Check:

   Missing line = no dual axis [OK]

Hint: Enable dual axis to show both bars and lines [OK]

Common Mistakes:

• Assuming data is missing without checking axes
• Blaming filters for line missing
• Not verifying mark types

5. You want to create a combo chart showing monthly Sales as bars and cumulative Profit as a line. Which steps should you follow?

hard

A. Use a pie chart for Sales and a line chart for Profit on the same axis

B. Create cumulative Profit bar chart, add Sales as line on single axis, no synchronization needed

C. Create Sales bar chart, create cumulative Profit calculated field, add Profit as line on dual axis, synchronize axes

D. Create Sales and Profit as separate charts, then combine in dashboard without dual axis

Solution

1. Step 1: Prepare measures

   Create a bar chart for Sales and a calculated field for cumulative Profit to show running total.

2. Step 2: Build combo chart

   Add Sales as bars and cumulative Profit as a line on a dual axis, then synchronize axes for clear comparison.

3. Final Answer:

   Create Sales bar chart, create cumulative Profit calculated field, add Profit as line on dual axis, synchronize axes -> Option C

4. Quick Check:

   Dual axis + cumulative calc + sync axes = correct combo [OK]

Hint: Use dual axis and cumulative calc for combo charts with running totals [OK]

Common Mistakes:

• Not creating cumulative calculated field for Profit
• Skipping axis synchronization
• Using single axis for different scales