This page answers some questions that we frequently receive about the curriculum. If you have questions that aren't answered here, try asking through one of our community channels. If it seems important enough or we get asked that question a lot, we will probably add it here.
Alternatively, you could contribute an answer yourself.
Some courses that require payment to access probably do exist on Coursera, but we don't put those on our curriculum. All Coursera courses that we put on the curriculum must, at minimum, be free to audit. For some courses, all course features are available for free; for others (especially those that are part of a specialization), you may only be able to access the lecture videos. (If you find the policies have changed for any courses on our curriculum, please tell us!)
Unfortunately, for some courses, Coursera's interface is very aggressive about convincing you that you have to pay.
You may see something like this on the course page:
When attempting to enroll in such a course:
Yes, because we have to draw a line. As soon as we require paid resources in the main curriculum, we might as well tell people to pay half a million dollars to attend a university. We are an Internet-based community of learners, not a business, so free is the most sensible price and ensures that the only price you need pay is the price of Internet access.
At the same time, we recognize that education is scarce resource and therefore requires payment to instructors to make it sustainable in the long term. Therefore, we respect the business model of websites like edX, which make their materials free but with some paid add-ons, like official certificates or extra interaction with course instructors.
So we only require that the learning materials of a resource be free to access, not that every possible add-on be free. It would be ideal if graded assignments were always free but if we had this requirement, we would have to exclude any resource that doesn't have graded assignments at all. Plus, there are other ways to get feedback on your work, and OSSU is a do-it-yourself education.
You have a few different options:
We have designed the curriculum to work for any of the above three styles.
If you just want to watch the videos, it is never necessary for any edX course on our curriculum.
CS50 doesn't use edX's grading system; it grades all assignments for free.
The Software Development courses have mostly free quizzes and assignments, but their Final Projects will only be graded by a human if you pay.
The strongest and most useful part of CS50 is the part where they teach C. We are retaining this in the curriculum for now because it is one of the few chances the student has to play with manual memory management in a (relatively) low-level language. By learning C, students will also have a much easier time getting through the following course, Nand2Tetris.
That being said, feel free to finish CS50 if you like it and want to.
We have several goals that we have to balance:
Therefore, not everything can be included, but we strive to be eclectic so that students are both employable and well-armed for change.
The curriculum assumes two things:
Without these assumptions, the curriculum would be out of control with trying to fill in your knowledge gaps. But those who for whatever reason didn't get all the way through high school math and physics are in luck: you can find the content you need on Khan Academy.
Of course, if you find that the curriculum is missing a pre-requisite for a course that isn't part of a normal high school curriculum, please let us know!