Archive for July 20, 2020

Proposal #1 to Change CS Education to Reduce Inequity: Teach computer science to advantage the students with less computing background

This is my second post in a series about how we have to change how we teach CS education to reduce inequity. I started this series with this post, making an argument based on race, but might also be made in terms of the pandemic. We have to change how we teach CS this year.

The series has several inspirations, but the concrete one that I want to reference back to each week is the statement from the University of Maryland’s CS department:

Creating a task force within the Education Committee for a full review of the computer science curriculum to ensure that classes are structured such that students starting out with less computing background can succeed, as well as reorienting the department teaching culture towards a growth mindset

We as individual computing teachers make choices that influence whether students with less computing background can succeed. I often see choices being made that encourage the most capable students, but at the cost of the least prepared students. Part of this is because we see ourselves as preparing students for top software engineering jobs. The questions that get asked on technical interviews explicitly drive how many CS departments teach algorithms and theory. We want to encourage “excellence.” But whose excellence do we care about? Is Silicon Valley entrepreneurial perspectives the only ones that matter? The goal of “becoming a great software engineer” does not consider alternative endpoints for computing education (see post here). Not all our students want those kinds of jobs. Many of our students are much more interested in giving back to their community, rather than take the Silicon Valley jobs that our programs aim for (see post here).

Please don’t teach students as if they are you. First, you (as a CS teacher, as someone who reads this blog) are wildly different than our normal student. Second, your memories of how you learned and what worked for you are likely wrong. Humans are terrible at reconstructing how their memory was at a prior time and what led to their learning. That’s why we need research.

In this post, I will identify four of the methods that are differential, that advantage the students with less computing background — there are many more:

  • Use Peer Instruction
  • Explain connection to community values
  • Use Parsons Problems
  • Use subgoal labeling

Use Peer Instruction

When I talk to computer science teachers about peer instruction and how powerful it is for learning, the most common response is, “Oh, we already do that.” When I press them, they tell me that they “have class discussions” or “use undergraduate teaching assistants.” Nope, that’s not peer instruction.

Peer instruction (PI) is a technical term meaning a very specific protocol. Digital Promise and UTeach are creating a set of CS teaching micro credentials, and the one that they have on PI defines it well (see link here). PI is where the teacher poses a question for the class for individual responses, students discuss their answers, students respond again, and the teacher reveals the answer and explains the answer. The evidence suggesting that PI really works is overwhelming, and it can be used in any CS class — see http://peerinstruction4cs.com/ for more information on how to do it. I use it regularly in Senior-level undergraduate courses and graduate courses. There are ways to do PI when teaching remotely, as I talked about in this post.

I’m highlighting PI because the evidence suggests that it has a differential impact (see study here). It doesn’t hurt the top students, but it reduces failure rate (measured in multiple CS courses) for students with less background (see paper here). That’s exactly what we’re looking for in this series — how do we improve the odds of success for students who are not in the most privileged groups.

Explain connection to community values

I blogged last year about a paper (see post here) that showed female, Black, Latino/Latina, and first-generation students take CS because they want to help society. These students often do not see a connection between what’s being taught in CS classes and what they want. That’s because we often teach to prepare students for top software engineering jobs — it’s a mismatch between our goals and their goals.

I don’t know if this is an issue in upper-level classes. Maybe students in upper-level classes have already figured out how CS connects to their goals and values. Or maybe we have already filtered out the CS students who care about community values by the upper-level and graduate courses.

CS can certainly be used to advance social goals and community values. Teach that. In every CS class, for everything you teach, explain concretely how this concept or skill could be used to advance social good, cultural relevance, and community values. If you can’t, ask yourself why you’re teaching this concept or skill. If it’s just to promote a Silicon Valley jobs program, consider dropping it. We are all revising our classes this summer for fall. It’s a good time to do this review and update.

Use Parsons Problems

Parsons problems (sometimes referred to as “mixed-up code problems”) are where students are given a programming problem, and given all the lines of code to solve the problem, but the lines are scrambled (I usually say “on refrigerator magnets”). The challenge is to assemble the correct program. My wife, Barbara Ericson, did her dissertation work (see post here) showing that Parsons problems were effective (led to the same learning as writing the programs from scratch or from debugging programs) and efficient (low time cost, low cognitive load). She also invented dynamically adaptive Parsons problems which are even better (for effectiveness and efficiency) than traditional Parsons problems.

Parsons problems work on-line, so they fit into remote teaching easily. I’ve been doing paper-based (and Canvas-based) Parsons for exams and quizzes for several years now (see post here). Parsons problems work great in lower-level classes. There is relatively little research on using them in upper-level and graduate courses — I suspect that they could be useful, if only to break up the all-coding-all-the-time framing of CS classes.

I’m highlighting Parsons problems for two reasons.

  • First, they’re efficient. As Manuel noted (as I quoted in my Blog@CACM post), BIPOC students are much more likely to be time-stressed than more privileged students. I’m reading Grading for Equity by Joe Feldman which makes this point in more detail (see website). Our less-privileged students need us to find ways to teach them efficiently. This is going to be a particularly concern during a pandemic when students will have more time constraints, especially if they, or a relative, or someone they live becomes ill.
  • Second, they are a more careful and finer-grained assessment tool (see this post). If you ask students with less ability to write a piece of code, you might get students who only get part of the code working, but you get little data from students who only knew how to write part of the code but get none of it working. Parsons problems help the students with less computing background to show what they do know, and to help the teacher figure out what they don’t know how to write yet.

Use subgoal labelling

Subgoal labelling is pretty amazing (see Wikipedia page). Even our first experiment with subgoal labelling for CS worked examples (see post here) has shown improvements in learning (measured immediately after instruction), retention (measured a week later), and transfer (student success on a new task without instruction). Since then, Lauren Margulieux, Briana Morrison, and Adrienne Decker have published a slew of great results.

The one that makes it on this list is their most recent finding (see post here). Subgoal labeling in an introductory computing course, compared to one not using subgoal labeling, led to reduced drop or failure rates. That’s a differential benefit. There was not a statistically significant improvement on learning (measured in terms of exam scores), but it kept the students most at risk of failing or dropping out in the course. That’s teaching to advantage the students with less background in computing. We don’t know if it works for upper-level or graduate classes — my hypothesis is that it would.

July 20, 2020 at 7:00 am 5 comments


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