Archive for November 21, 2014

Programming with Pseudocode, Keeping Student Interest, the Need for School, and International Curricula: Trip Report on WiPSCE 2014

First week of this month, Barb and I went to Berlin for WiPSCE 2014 conference. See the program here and the proceedings here, and the post on my keynote here. Let me tell you about some of the interesting things I heard there.

We heard about so many international CS curricula efforts. Tim Bell talked about different levels of programming activity going on in different curricula (all the images in this blog post are from me snapping pictures of presentations).


We heard about Austrian efforts, Flemish efforts, and programs I was aware of in the UK, New Zealand, Germany, Israel, and the United States.  I had not previously hear much about Poland in CS Ed, but they’ve been including computing in their curriculum for a long time.


Quintin Cutts (Code or (not Code) – Separating Formal and Natural Language in CS Education) talked about a problem that they’re having in Scotland that we’re also facing in the US with the CS Principles effort. There are several different programming languages in use in schools. Nobody wants to be the bad guy to say “You have to use X (maybe Scratch? Alice? App Inventor? Python?), because that’s what the national test will be in.” So, national test-developers are creating pseudocode languages that aim to be understandable without getting hung up on syntax. Scotland has one that’s made up of bits and pieces of other languages (which they call “Haggis” — seriously!). The problem is that if a piece of code is never expected to run, it can have assumptions within it that would have to be cleared up to build a runtime system.  Quintin showed how even simple examples of the pseudocode from their national test have all kinds of logical inconsistencies.

It’s a real problem. Allison Elliott Tew’s dissertation (see here for post) showed that weakest performing students had the worst time transferring their knowledge from whatever language they learned to a pseudo-code. That means that your top students are going to be fine with a pseudo-code test, but your bottom students are not going to do well at all — they won’t know all the concepts, and they’re going to trip over the language. A pseudo-code test is going to be another barrier to underprepared students getting into CS.

Now, once you get them in the door, how do you keep them there? One interesting paper (Scratch vs. Karel – Impact on Learning Outcomes and Motivation) compared student interest in using Scratch or Karol the Robot. Scratch is a blocks-based language, and Karol was programmed in a text-based language. Students liked Scratch and performed better with it, but felt that Karol was more “real-life” and thus was more motivating for doing more in CS later. Betsy DiSalvo found similar results with her Glitch students. When comparing Alice and Python, students liked what they could produce with Alice, but felt that Python was more like what real programmers did and was consequently more motivating for some students.  This paper has had me thinking, “Maybe we should bring Logo back?”  It’s text-based like Karol, designed for students, and we have LOTS of books and other materials available for Logo across the curriculum.

Leigh Ann DeLyser talked about her work with CS NYC (Software Engineering Students in the City). It’s a remarkable program: 1900 students applied for 120 slots, and the selection among the qualified students was by lottery. They did pre and post surveys around the first year of the program, with questions like “Would you like to study CS or SE after this semester?” or “Want to be a computer scientist or software engineer one day?” Females lost much more interest in a future computing career then males.


Finally, the talk that has most been in my thoughts since the conference was by Debby Fields and Yasmin Kafai on their Scratch study (Programming in the Wild: Patterns of Computational Participation in the Scratch Online Social Networking Forum). They studied 5000 visitors to the Scratch website in the first quarter of 2012. First big finding — most of them don’t do much. 55% visit but don’t do anything. The other 45% engage at a variety of levels, and the levels are pretty much gender-balanced.  The most active participants are about evenly split male-female.


Debbie and Yasmin defined four “classes” of programming activity based on the programs that these users uploaded to the Scratch website. Booleans are a big differentiator, as are variables and random numbers. The below figure describes how much of each kind of programming block appears in each class of programs, and what percentage of programs they saw land in each class.


Here’s the disappointing part: The highest level of programming activity was almost all boys. Girls don’t go much beyond the simplest programming.


Now, we don’t know much about ages or where these students are or their ethnic group. As Debby pointed out, age and location are self-reported on the Scratch website, and it’s remarkable how many 100 year old Scratch programmers there are in Antartica. Their data suggest that informal education activities like Scratch (or Kahn Academy or MOOCs) are unlikely to reach a broad range of users. Debby pointed out that what students are building influences what students do. If Scratch programmers can tell stories without booleans, how do you motivate more advanced programming actvities if they’re only story-telling? If we want to reach more diverse students, and we want to encourage more kinds of activities, we need school. We need formal education to reach everyone.

November 21, 2014 at 8:51 am 12 comments

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