Applies to: @RISK for Excel 5.x and Up

 

Convergence Monitoring in @RISK

Overview:
Convergence monitoring ensures simulated outputs stabilize before the simulation stops. Set Iterations → Auto and configure the Convergence tab in Simulation Settings.

Key Points:

• Monitor mean, standard deviation, and/or a percentile.

• Specify tolerance (e.g., 3%) and confidence level (e.g., 95%).

• Simulation stops when the selected measures have a 95% chance of being within the specified tolerance.

• If multiple measures are selected, all must meet the convergence criteria.

Frequency of Testing:

• The “Calculate every ___ iterations” setting determines how often @RISK checks convergence.

• More frequent checks may reduce total iterations but add computational overhead; less frequent checks may require more iterations.

Results Window:

• Opens automatically during simulation.

• Status column shows OK for converged outputs; numbers 1–99 indicate the estimated % of iterations completed toward convergence.

• Example: Status 23 after 10,000 iterations estimates ~43,500 iterations needed for convergence (10,000 ÷ 23%).

 

Related Articles

Convergence by Testing Percentiles

More Than 50,000 Iterations to Converge

Convergence by Standard Deviation: Always Same Number of Iterations