Problem Sets

In this section, Dr. Diviya Sinha describes how she and the course team create and grade the problem sets for 7.013.

In this course, students are assigned seven long problem sets, roughly one for every two weeks. These problem sets are designed to get students to understand and apply lecture material in order to solve problems. For more discussion about our goals for problem sets, please read Prof. Hazel Sive’s comments on Teaching Students to Solve Problems. This section focuses on how we create the problem sets and their solution keys, and how we grade problem sets.

Developing Problem Set Questions

For each problem set, I think about the key concepts we want to cover and work on developing questions. I often look at news articles to help me develop the problem set questions. For example, we have three lectures on cell biology in 7.013. I came across an article on the MIT homepage titled, “Living cells say: Can you hear me now?” The article discusses how a cell communicates with another neighboring cell. It was written in a very nice way, and the work was done by an MIT professor, so we incorporated it into problem set 4 and problem set 5. A lot of the problems are similarly grounded in very current research.

Prof. Sive and Prof. Jacks often send me ideas and problems that they would like to include. For example, for the first problem set this semester, Prof. Jacks suggested that we include a question about the DNA that is present in all the cells of just one person: How many trips can you take to the sun with the length of all the DNA present in one person’s body? We incorporated this as a question, and the students really liked it.

I am always in touch with the professors when I’m developing the course materials, and they offer feedback promptly.

Problem Set Solutions

For each problem set, we have an extra staff meeting. When I write problem sets, I eventually become sort of immune to any issues the problem sets might have because I’m so familiar with them. The TAs and I each write out a complete set of answers for all the questions on every problem set. For the most part, the TAs’ answers are the same as mine, but once in a while their solutions have parts that aren’t in my prepared solution key. So, the TAs’ answers can help me understand how I need to improve or add onto each problem set and solution key. I find it very helpful.

Grading

Grading responsibilities are split between TAs and undergraduate graders who are undergraduate students who did well in the course in past semesters. If a graduate TA is teaching two recitation sections, the TA might grade the problem sets for one of the recitation sections, and the undergraduate grader might grade the problem sets for the other recitation section. For the next problem set, they switch. This way, the TA gets a picture of how all of the students are doing without having to shoulder all of the grading responsibilities.

This is a big class, and we strive to be consistent when it comes to grading. To promote consistency, the graders, TAs, and I maintain a shared Google document. If a grader or a TA comes across an answer on the problem set that is not part of the solution key and they want to accept it, then they post their comments on the Google document so everyone can see it. If it’s accepted by me or the TA who is in charge of that problem set, then everyone who comes across that same type of answer can accept it.