Applies to:
@RISK 6.x and Up, Professional and Industrial Editions

Parameter Entry Tables vs. Risk Categories in @RISK for Project

A parameter entry table and a risk category both let you select a group of tasks and apply variation, but they serve slightly different purposes.

Choosing Between Them

• Parameter Entry Table: Best when you want to display parameters (min, most likely, max) in dedicated columns for easy editing. Only one table can exist per project.

• Risk Category: Best when you want a group of tasks to vary by the same percentages or amounts. Multiple categories can exist with different variations.

You can apply either tool to any numeric or date field, though most users vary the Duration field.

Using Both Tools
Both can exist in the same project, but you should not apply both to the same tasks.

Creating a Parameter Entry Table

1. Click Project » Model Tools » Parameter Entry Table.

2. Select the field (column) to vary.

3. Choose the type of variation.

4. Under Build Entry Table For, choose All Tasks or Selected Tasks. Milestones and summary tasks are ignored automatically.

5. If Selected Tasks, click Add to choose tasks manually or Add Marked to select tasks based on criteria (e.g., duration of 1 day or a text field like “Construction”).

6. If project managers will update the MPP file, check Also Add Entry Table to MPP.

Creating Risk Categories

• Similar to parameter entry tables but allow multiple categories with different distribution functions.

• Select distributions and tasks in the same way, but @RISK writes the variation directly into the selected field using functions like RiskVary.

• You can create additional categories or modify existing ones as needed.

Key Differences Summary

• Parameter entry tables are for dedicated columns and easy editing; only one per project.

• Risk categories can have multiple groups, directly writing variations into task fields.

• Both can coexist, but avoid overlapping tasks.

Summary Table: