Once you've genrefied, you need to keep tabs on circulation, what's moving, and how students are responding to the changes. Can they find what they're looking for independently and easily or are they having problems? What needs tweaking or completely changed? Because the goal is to make finding books easier for your students, it's important to just talk to them or get them to go find a title to see how it works for them. Give them autonomy and independence!
I also made a huge deal about a suggestion box or some way for students to request books to add to the collection. Once they start being able to locate the titles they wanted, they usually see other authors, titles, and books they'd love to read. Additionally, because authors sometimes have books in multiple genres, it's fun to expand their horizons to read something in another genre because they love the author. Again...be flexible and open to doing what it takes to make this an amazing experience for your students!
To that end, here's some of the data collection I have done:
Informal/Anecdotal DataFormal Data
Student Advisory Committee Discussions Circulation Data by Month
Student/Teacher ConversationsCirculation Data by Dewey 100s
While technically you can't really compare student populations at different campuses, I used data from the two schools our students came from to compare the first couple of years.
Regardless of what data you collect or how you collect it, data should inform your curation, purchasing, and organization each year. Involve students, teachers, and any other stakeholders in your decisions to ensure your library is relevant and the best it can be for your students.