SIMUL8 Tip – validate or verify?

SIMUL8 Tips, Technical Corner



When do you validate and when do you verify? The difference between validation and verification is something that we are asked all the time by our new users, and it’s understandable given it’s easy to confuse the meanings.

Once you have built your simulation you will need to validate and verify it.

What comes first?

Verification comes before validation. Put simply verification involves making sure that the simulation you have built is correct – i.e. that there are no mistakes in your logic.

This means checking that the simulation has been built the way you intended to build it. This is particularly important in the case of simulations that involve visual logic programming, as it is easy to make a mistake you might not notice instantly.

One way to verify a simulation is to carefully experiment with the simulation, watching both the animated screen and performance measures to see if the changes you see are reasonable in light of changes you make to the input of the simulation (such as demand, numbers and speeds of machines etc.)

Careful examination of the simulation’s behaviour will allow you to see and remove most mistakes or misunderstandings in the simulation building.

Validation

Only after verification is complete you can begin validating your simulation.

Validation is checking that the correctly built simulation behaves the same as the system in the real world would.

Validation of a process that already exists can be carried out my comparing the simulation to results/outputs of the real system by using historical data.

If the process does not already exist validation can be carried out by talking to experts about the process and seeing if the simulation is accurate, or by comparing it to previous research that exists on the process.

The validation stage of testing involves ensuring that you have solved the correct question. You need to ensure that the simulation you have built behaves in the same way as the real-life system you intended to simulate.

It would be easy to miss these stages out in the excitement of finishing your simulation and to go straight to finding the solution to your problems, but checking for mistakes now will avoid costly errors further down the process.

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It would be easy to miss these stages out in the excitement of finishing your simulation and to go straight to finding the solution to your problems but checking for mistakes now will avoid costly errors further down the process.

If you have something you would like us to write a tip on then let us know and we’ll see what we can do.