Parameters in Tableau are dynamic values that can be used to replace constant values in calculations, filters, and reference lines. They allow users to interact with the data and customize their views without altering the underlying data.

1. Definition: A parameter is a global variable that can be used in calculations, filters, and other areas of Tableau.
2. Types of Parameters:
   • String: Text values.
   • Integer: Whole numbers.
   • Float: Decimal numbers.
   • Boolean: True/False values.
   • Date: Date values.
   • Date & Time: Date and time values.

1. Open Tableau and connect to your data source.
2. Right-click in the Data pane and select Create Parameter.
3. Name the Parameter: Give your parameter a meaningful name.
4. Data Type: Choose the appropriate data type (String, Integer, Float, Boolean, Date, Date & Time).
5. Current Value: Set the initial value of the parameter.
6. Allowable Values:
   • All: Any value can be entered.
   • List: A predefined list of values.
   • Range: A range of values with a specified minimum and maximum.

Parameters can be used in calculated fields to create dynamic calculations.

1. Create a Parameter: Follow the steps above to create a parameter named "Sales Threshold".
2. Create a Calculated Field:
   • Right-click in the Data pane and select Create Calculated Field.
   • Name the calculated field "High Sales".
   • Enter the following formula:

     IF [Sales] > [Sales Threshold] THEN "Above Threshold" ELSE "Below Threshold" END
     

3. Use the Calculated Field: Drag the "High Sales" field to the Color shelf on the Marks card to visually differentiate sales above and below the threshold.

Parameters can be used to create dynamic filters that allow users to control the data displayed.

1. Create a Parameter: Create a parameter named "Select Region" with a list of regions.
2. Create a Calculated Field:
   • Name the calculated field "Region Filter".
   • Enter the following formula:

     [Region] = [Select Region]
     

3. Use the Calculated Field: Drag the "Region Filter" field to the Filters shelf and set it to True.

Parameters can be used to create dynamic reference lines that users can adjust.

1. Create a Parameter: Create a parameter named "Reference Line Value" with a float data type.
2. Add a Reference Line:
   • Right-click on the axis where you want to add the reference line and select Add Reference Line.
   • In the Value dropdown, select the "Reference Line Value" parameter.
   • Customize the appearance of the reference line as needed.

1. Create a Parameter: Create a parameter named "Sales Target" with a float data type and a range of values.
2. Create a Calculated Field:
   • Name the calculated field "Target Achievement".
   • Enter the following formula:

     IF [Sales] >= [Sales Target] THEN "Target Met" ELSE "Target Not Met" END
     

3. Create a Visualization:
   • Drag "Sales" to the Rows shelf and "Category" to the Columns shelf.
   • Drag the "Target Achievement" field to the Color shelf on the Marks card.
4. Add a Reference Line:
   • Add a reference line to the Sales axis using the "Sales Target" parameter.

1. Parameter:

   Name: Sales Target
   Data Type: Float
   Current Value: 50000
   Allowable Values: Range
     - Minimum: 0
     - Maximum: 1000000
     - Step Size: 1000
   

2. Calculated Field:

   Name: Target Achievement
   Formula: IF [Sales] >= [Sales Target] THEN "Target Met" ELSE "Target Not Met" END
   

3. Visualization:
   • Drag "Sales" to Rows.
   • Drag "Category" to Columns.
   • Drag "Target Achievement" to Color.
4. Reference Line:
   • Add a reference line to the Sales axis using the "Sales Target" parameter.

• Common Mistake: Forgetting to use the parameter in a calculated field or filter.
  • Tip: Always ensure that the parameter is referenced in your calculations or filters.
• Common Mistake: Setting an inappropriate data type for the parameter.
  • Tip: Double-check the data type to ensure it matches the expected input.

Parameters are powerful tools in Tableau that allow for dynamic and interactive visualizations. By understanding how to create and use parameters, you can provide users with the ability to customize their views and gain deeper insights from their data. In the next module, we will explore creating maps in Tableau, which will further enhance your data visualization skills.