Trend lines in Tableau - Real Business Scenario

Scenario Mode

👤 Your Role: You are a sales analyst at a retail company.

📋 Request: Your manager wants to understand how monthly sales have changed over the past year and identify any trends.

📊 Data: You have monthly sales data for the last 12 months, including the month and total sales amount.

🎯 Deliverable: Create a line chart showing monthly sales with a trend line to highlight the sales trend over time.

Sample Data

Month	Sales
2023-07	12000
2023-08	13500
2023-09	12800
2023-10	14000
2023-11	15000
2023-12	16000
2024-01	15500
2024-02	16500
2024-03	17000
2024-04	17500
2024-05	18000
2024-06	18500

1

Step 1: Connect your data source in Tableau and load the monthly sales data.

No formula needed. Just connect and import the data.

Expected Result

Data with columns 'Month' and 'Sales' is available in Tableau.

2

Step 2: Create a line chart with 'Month' on the Columns shelf and 'Sales' on the Rows shelf.

Drag 'Month' to Columns and 'Sales' to Rows.

Expected Result

A line chart showing sales values for each month.

3

Step 3: Add a trend line to the line chart to show the sales trend over time.

Right-click on the chart, select 'Trend Lines' > 'Show Trend Lines'. Choose 'Linear' model.

Expected Result

A linear trend line appears on the chart showing the overall sales trend.

4

Step 4: Format the chart for clarity: add axis titles, chart title, and ensure date axis is continuous.

Edit axis titles to 'Month' and 'Sales Amount'. Set chart title to 'Monthly Sales Trend'.

Expected Result

The chart is clear and easy to understand with proper labels.

Final Result

Monthly Sales Trend

Month ->
2023-07 ──●────●────●────●────●────●────●────●────●────●────●────● 2024-06
          │    │    │    │    │    │    │    │    │    │    │    │
Sales    12k  13.5k 12.8k 14k  15k  16k  15.5k 16.5k 17k  17.5k 18k  18.5k
Trend Line: A smooth upward line showing increasing sales over months.

✓Sales have generally increased month over month in the last year.

✓The trend line confirms a positive upward trend in sales.

✓There are small fluctuations, but the overall direction is growth.

Bonus Challenge

Add a forecast for the next 3 months based on the trend line to predict future sales.

Show Hint

Use Tableau's built-in forecasting feature by right-clicking the chart and selecting 'Forecast' > 'Show Forecast'.