The Dyslexia-SpLD Trust came to us because their existing self-assessment framework was inflexible and costly to maintain. We had a track record of building custom web applications using Drupal 7, so we sat down with them to discuss what they needed.
Initially we looked at the quiz module for self-assessment, but due to their need to have a confidence level, as well as a particular response, for each statement, we decided to build something from scratch using Drupal's Entity system and its excellent views integration.
This was a code-heavy project, with a fair proportion of programming time, but needed special care and attention on the design side of things to make sure that the visuals were friendly to everyone, including those with learning difficulties, and complied with the WCAG.