Tableau parameters are user-controlled inputs that can change values in calculations, filters, reference lines, and data source connections at runtime. They are the mechanism for building dashboards that respond to user choices — scenario comparisons, dynamic metric selection, threshold-based highlighting, and conditional logic that would otherwise require separate views for each option.
Tableau parameters are workbook-level variables that users can change at runtime to control calculations, filters, reference lines, and other dynamic elements. A parameter is a named value with a defined data type — integer, float, string, date, or boolean — and an optional set of allowed values that constrains what users can select. When a user changes a parameter value through the parameter control in a published view, any calculations or configurations that reference the parameter update immediately.
Parameters are the primary mechanism for building dashboards that respond to user choices rather than requiring separate views for each analytical scenario. A dashboard that allows users to switch between revenue, margin, and units metrics; compare actual performance against budget or prior year; set alert thresholds; or choose a rolling window size — all of these are parameter-driven.
Parameter Data Types and Allowed Values
Parameters support six data types, each suited to different use cases:
**Integer and Float** — numeric parameters, for quantities, thresholds, percentages, and multipliers. Allowed values can be defined as a range (min/max with a step size) or a list of specific values.
**String** — text parameters, for selecting metric names, dimension members, or SQL fragments. Allowed values are typically a list of valid strings.
**Date and Datetime** — temporal parameters, for date range selection, comparison period selection, or time-based thresholds.
**Boolean** — binary parameters, for yes/no toggles. Less common than the other types.
The allowed values setting controls what users can select:
**All** — any value the user types is accepted. Useful for numeric thresholds where the valid range is not easily bounded.
**List** — a defined set of allowed values, each with an optional display alias. The list appears as a dropdown or radio button control. Aliases allow displaying "Revenue" while the underlying value is "SUM([Revenue])" — a formula fragment that will be used in a calculation.
**Range** — a min/max range with a step size, displayed as a slider. Appropriate for numeric parameters where fine-grained control within a bounded range is needed.
Parameters in Calculations
The primary use of parameters is in calculated fields. A calculation references a parameter by name, and the calculation result changes as the parameter value changes.
**Dynamic metric selection** — a string parameter named "Selected Metric" with allowed values "Revenue", "Margin", "Units" can drive a calculation:
IF [Selected Metric] = "Revenue" THEN [Revenue]
ELSEIF [Selected Metric] = "Margin" THEN [Gross Margin]
ELSE [Units Sold]
END
Place this calculation on the rows shelf in place of a fixed metric, and the chart updates when the user changes the parameter.
**Dynamic comparison** — a string parameter for comparison type drives period-over-period analysis:
IF [Comparison Type] = "vs Prior Year"
THEN [Revenue] - LOOKUP(ZN([Revenue]), -52)
ELSE [Revenue] - [Budget Revenue]
END
**Threshold highlighting** — an integer parameter named "Alert Threshold" drives a conditional colour calculation:
IF SUM([Defect Count]) > [Alert Threshold] THEN "Above Threshold" ELSE "Below Threshold" END
**Dynamic top-N filters** — an integer parameter drives a top-N filter calculation:
RANK(SUM([Revenue])) <= [Top N]
Parameters in Filters
Parameters can drive filter conditions through calculated fields. A parameter-based filter differs from a standard quick filter in that it does not expose the full list of dimension members — it applies a condition based on the parameter value:
A date range parameter pair (Start Date and End Date) combined with a filter calculation:
[Order Date] >= [Start Date] AND [Order Date] <= [End Date]
This produces a date range control without the performance cost of a relative date filter that generates a large number of marks.
Parameters in Reference Lines
Reference lines, reference bands, and distribution lines on axes can be driven by parameters directly — no calculated field required. In the reference line configuration dialog, select the parameter as the value source. A threshold parameter on a bar chart's axis creates a visual target line that users can adjust interactively.
This is one of the highest-value parameter patterns for operational dashboards: a manager can set a target value, and the reference line immediately shows which items are above and below it.
Parameter Actions
Parameter actions — introduced in Tableau 2019.2 — allow dashboard interactions to change parameter values. When a user clicks or hovers on a mark, a parameter action can update a parameter to a value derived from that mark.
Common parameter action patterns:
**Click to select** — clicking a mark in a chart sets a parameter to the dimension value of that mark. Other views on the dashboard filter to show detail for the selected member. This is an alternative to filter actions that allows the selected context to persist after the user deselects.
**Click to compare** — clicking a mark in a bar chart sets a "Selected Region" parameter to the clicked region. A line chart on the dashboard shows the trend for the selected region highlighted against the others.
**Hover tooltip context** — a hover parameter action updates a parameter as the user moves over marks, driving a tooltip visualisation that shows data specific to the hovered mark.
Parameter Actions vs Filter Actions
The choice between parameter actions and filter actions affects both behaviour and performance:
**Filter actions** — easy to configure, apply filters to selected views, reset when the user deselects. Good for drill-down patterns where the user selects a context and explores detail.
**Parameter actions** — more configuration required (need calculated fields that reference the parameter), but the parameter state persists when the user deselects, and parameters can drive calculations that filter actions cannot. Parameter actions are the right choice when the selected value needs to drive calculations, reference lines, or cross-datasource behaviour.
Parameters Across Data Sources
Parameters are workbook-level objects, not data source objects. A single parameter can be referenced in calculations across multiple data sources in the same workbook. This makes parameters useful for cross-datasource comparison logic — a metric selection parameter used in calculations against both an actuals data source and a budget data source maintains consistent filtering behaviour across both.
Parameter Publishing and Sharing
Parameters are published as part of the workbook. When a view is embedded or published, the parameter control appears in the view for users to interact with. Parameters can be shown or hidden selectively; a parameter used in back-end calculations but not intended for user interaction should be hidden from the view.
Default parameter values are set in the workbook definition. For published views, the current parameter state can be passed via the URL using the :param query parameter — useful for linking to a view with a specific parameter state pre-set.
Our Tableau consulting practice builds analytically sophisticated Tableau dashboards using parameters and parameter actions for enterprise clients — contact us to discuss advanced dashboard design for your analytics environment.
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