HOW DO WE EVALUATE THE DESIGN? Now that we have analyzed how the users use the tool and designed one or more improvements, it is time for the Evaluation phase. One of the rst questions to ask ourselves is if it will be more cost-eective to go straight to code or to pre-visualize the changes to the tool. e next question to ask is if there are current users or users with a similar prole available to validate the interface. If users are available, we can do user tests. If not, we can perform a heuristic evaluation while we wait for users to become available.