My suggestion would be to base your rubric on the requirements of the PT, but also encourage your students to go beyond the baseline requirements. So for the Web Page PT at the end of Unit 1, the requirements of the project are laid out in the exercise description as:
- A profile image
- Your name
- A short bio about yourself. Who are you? What do you like to do? Make a list of at least 5 things.
- What you would like to learn in AP CS Principles?
- Add a link to one of your favorite web pages that you’ve made so far. To do this:
- Go to the exercise that you want to link to
- Click on the “See HTML in new window” button
- This is your webpage that you made for that exercise. Copy the URL for this webpage and link to it from your homepage.
- Add links to more than one exercise if you like!
- Anything else you want to add! This is your site, make it yours!
So meeting these requirements would qualify as satisfactory, not meeting each of these requirements would qualify as needing improvement, and going beyond these requirements (maybe adding more information to the homepage and adding your own styling) would qualify as exceeding expectations.
The Practice PTs start off simple and get more and more rigorous as the course progresses. The Web Development Practice PT is relatively simple, and the Practice PTs in the Functions and Parameters, Digital Information, Internet and Data units are more representative of the actual Performance Tasks students will need to create for their AP examination. For these Practice PTs students will both 1) create a computational artifact such as a program or video, and 2) write responses to questions about their artifact and the development process.
For these Practice PTs you could look to the AP scoring guide as a basis for your rubric. You can find information about the AP performance tasks, sample student submissions from last spring, and sample scoring guides here: http://apcentral.collegeboard.com/apc/public/exam/exam_information/231726.html