Why don't we make all exercise solutions public?

David Diez February 15th, 2021

We've had regular requests for access to the exercise solutions manual from students, such as those wanting to check work or lead study groups, as well as parents looking to help their kids. I understand our policy of not providing solutions to students and parents may seem insensitive, so I wanted to explain why it's our policy and we don't have any plans to change it. Beyond this, I would like to highlight that about 95% of content on the site is available to anyone, including full textbooks with solutions to odd numbered exercises in the back, slides, labs, videos, classroom activities, and more.

First, some key considerations that we are aware of:

  1. In many classes, homework contributes to the grade.
  2. Homework is frequently chosen from questions in the course textbook.
  3. If solutions are shared with a handful students, the solutions will likely show up online or shared privately among students.
  4. Students with more financial resources are likely able to access solutions by paying someone else to do their work.

Now with those considerations in mind...

  1. Because of #1 and #2, many teachers will become frustrated with our books if they cannot use some of the textbook exercises for graded homework. This will lead some of those teachers to adopt another book, likely at a cost to each student of $100 to $200. This is the primary reason we do not release solutions: it undermines the utility of our textbooks and the likelihood that teachers will use them.
  2. If solutions are readily available, the usefulness of student collaborations and study groups diminishes, possibly leading more students to "go it alone". However, these collaborations are important, because they help students further their understanding by working out problems together.
  3. If a student can rely on a solution manual, the student may always get the correct answer on homework by following the provided answer while sometimes not understanding the solution. This can lead to a false sense of confidence.
  4. We cannot reasonably bend our rule for parents. As a first consideration (among many), some students would then pretend to be a parent, but we cannot quickly/efficiently distinguish between students and parents online.
  5. Issue #4 is a problem in our eyes, but there isn't a reasonable way for us to address this issue.
  6. If teachers reduce usage of our resources, then it will be harder to recruit volunteers to develop open and free resources. In this way, releasing solutions would undercut our future plans to greatly expand the already huge set of free resources that we provide.
  7. Lastly, most even-numbered exercises are similar to an adjacent odd-numbered exercise, so if someone is stuck on an even-numbered exercise, check nearby odd exercises. There's probably one to work through where the same ideas can then be applied to the even-numbered exercise.

I hope this clarifies why we don't share the solutions manual with students or parents. In the end, if this policy wasn't in place, it would lead to many teachers choosing a different, more expensive textbook, and that would be much worse for students and parents.