Data validation and data tables in Excel can work together to create a more robust what-if analysis scenario. Here's how:

1. Set Up Data Validation:

* Identify the input cell(s) where you want to allow users to enter different values for their what-if analysis.
* Use the Data Validation tool (Data tab > Data Tools group > Data Validation) to define allowed values for these cells. You can choose various options like:
* List: Restrict entries to a predefined list of values.
* Range: Limit entries to a specific numerical range.
* Decimal: Allow only decimal numbers with specific criteria.
* Custom formula: Apply a custom formula to validate entries.

2. Create a Data Table:

* After setting up data validation, identify the formula cell that calculates the output you want to analyze based on the input(s).
* Go to the Data tab, and in the Data Tools group, click on "What-If Analysis" and choose "Data Table."

3. Define the Data Table Range:

* In the "Row input cell" field, select the cell containing the input value you want to vary for the analysis. (This should be the cell with data validation applied.)
* In the "Column input cell" field (optional), if you have a second variable input cell with data validation, select it here. This allows you to analyze the impact of two changing factors simultaneously.
* Define the "Table range" where Excel will display the results of different input values. This can be a blank range of cells.

4. Run the Analysis:

* Click "OK" to generate the data table. Excel will automatically populate the table range with various combinations of the input values based on your data validation rules.
* For each combination, the formula cell will be recalculated, showing the corresponding output in the data table.

Benefits of Combining:

* Controlled Input: Data validation ensures users only enter valid values for the what-if analysis, preventing errors and maintaining data integrity.
* Flexibility: You can define different scenarios by adjusting the allowed values within the data validation rules.
* Efficiency: The data table automatically generates multiple calculations based on the validated inputs, saving you time and effort.

Example:

Imagine you have a sales commission formula that calculates commission based on the number of units sold (input cell with data validation for a range) and the unit price (another input cell with data validation for a specific range). By combining data validation and a data table, you can quickly see how your commission changes with different sales volumes and unit prices.

This approach allows you to explore various possibilities within the allowed ranges defined by data validation, providing a more comprehensive what-if analysis.