It Will Never Work in Theory

An Empirical Investigation into Programming Language Syntax

Posted Jan 29, 2014 by Greg Wilson in controlled experiments, programming languages


Andreas Stefik and Susanna Siebert: "An Empirical Investigation into Programming Language Syntax." ACM Transactions on Computing Education, 13(4), Nov. 2013.

Recent studies in the literature have shown that syntax remains a significant barrier to novice computer science students in the field. While this syntax barrier is known to exist, whether and how it varies across programming languages has not been carefully investigated. For this article, we conducted four empirical studies on programming language syntax as part of a larger analysis into the, so called, programming language wars. We first present two surveys conducted with students on the intuitiveness of syntax, which we used to garner formative clues on what words and symbols might be easy for novices to understand. We followed up with two studies on the accuracy rates of novices using a total of six programming languages: Ruby, Java, Perl, Python, Randomo, and Quorum. Randomo was designed by randomly choosing some keywords from the ASCII table (a metaphorical placebo). To our surprise, we found that languages using a more traditional C-style syntax (both Perl and Java) did not afford accuracy rates significantly higher than a language with randomly generated keywords, but that languages which deviate (Quorum, Python, and Ruby) did. These results, including the specifics of syntax that are particularly problematic for novices, may help teachers of introductory programming courses in choosing appropriate first languages and in helping students to overcome the challenges they face with syntax.

This paper is a follow-on to one we wrote about a couple of years ago that generated a lot of comments, many of them unpleasant. Stefik responded then, and he and Siebert have now followed up with several more studies that show:

  1. Programming language designers needlessly make programming languages harder to learn by not doing basic usability testing. For example, "...the three most common words for looping in computer science, for, while, and foreach, were rated as the three most unintuitive choices by non-programmers."
  2. C-style syntax, as used in Java and Perl, is just as hard for novices to learn as a randomly-designed syntax. Again, this pain is needless, because the syntax of other languages (such as Python and Ruby) is significantly easier.

They have also developed a technique called Token Accuracy Maps to make detailed studies of language syntax more methodical, and are using this to improve the design of a new language called Quorum that, wonder of wonders, incorporates feedback from studies of novice programmers to eliminate stumbling blocks.

I would like to see every proposed change to widely-used languages go through similar testing before being incorporated into standards. More than that, I would like to see programmers demand this kind of evidence from language designers (and each other). I suspect that would have a lot more impact than yet another type system or any number of sermons on the beauty of functional programming.

Note that this paper is available from the author's website, but only after a redirect to an ACM website that makes you wait a few seconds for another redirect, because that's what the ACM does to encourage people to take research seriously.

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