Testing is key to making usable forms - the opinions of the organization and the designer pale in comparison to the experience of actual users when they approach the form.
At the very least, do a "hey you" test - grab someone who is not familiar with the project and ask them to go through the form while you observe and take notes. It's quick and dirty, but better than nothing.
Better yet, do lab testing.
- The author suggests that five users is usually enough - that after five, you get diminishing returns - however, five users results in a 20% margin of error - there's a strong chance that errors are being missed and false positives are being generated.
- Ideally, a test is done with "real" users -a representative sample of the kinds of individuals who will actually use the form.
- Where answers are not slot-in, you may need to provide information for the test for them to reference
- In addition to observing their behavior, ask qualitative questions about their experience
A "paper test" can be useful, but it is not as good as having users interact with a functional prototype.