It has become common practice in many areas to prototype or mockup designs before anything is produced. In this way you can to be sure the product delivers what the customer wants and avoid wasting time and money creating something of no value.
In software development a number of user-centered design methodologies include such mockups as a central aspect of their approach. Screen mockups help to uncover unexpected problems with the new design and allow alternatives to be explored with the users before committing to particular layouts and functionality. They can also help to encourage more detailed user feedback from a wider audience, because it is far easier for users to review and comment upon a series of screenshots than it is to read through a series of documents. This is particularly true if you are trying to obtain feedback from large populations such as students.
When deciding if you should use mockups, it is important not to focus simply on the scale of the change being proposed. Getting that small change to Student Self-Service right could be more important to the institution than a large change to an administrator screen given the relative size of the two user populations.
The other factor to consider is the time required to create the mockups. Previously we used graphics or presentation packages (Photoshop, Paint, PowerPoint etc) but found this to be a lengthy process. It also meant that mockups could not be changed dynamically during a meeting with users.
We found that switching to a dedicated mockup utility significantly reduced the time required by about 75% in comparison with general office applications. There are a large number of free/low cost mockup tools available and when choosing a product it is important to select something that suits the way your organization works. For us a key factor was that our functional team creates the mockups so the product needed to be one they felt comfortable with.
Mockups should not be seen as a replacement for traditional project documentation, but instead as a quick and useful way to get feedback, validate your design and ensure you deliver a solution the users want.