To What Extent Cognitive-Driven Development Improves Code Readability?

Cognitive-Driven Development (CDD) is a coding design technique
that aims to reduce the cognitive effort that developers place in
understanding a given code unit (e.g., a class). By following CDD de-
sign practices, it is expected that the coding units to be smaller, and,
thus, easier to maintain and evolve. However, it is so far unknown
whether these smaller code units coded using CDD standards are,
indeed, easier to understand. In this work we aim to assess to what
extent CDD improves code readability. To achieve this goal, we
conducted a two-phase study. We start by inviting professional
software developers to vote (and justify their rationale) on the most
readable pair of code snippets (from a set of 10 pairs); one of the
pairs was coded using CDD practices. We received 133 answers.
In the second phase, we applied the state-of-the art readability
model on the 10-pairs of CDD-driven refactorings. We observed
some conflicting results. On the one hand, developers perceived
that seven (out of 10) CDD-driven refactorings were more readable
than their counterparts; for two other CDD-driven refactorings,
developers were undecided, while only in one of the CDD-driven
refactorings, developers preferred the original code snippet. On
the other hand, we noticed that only one CDD-driven refactorings
have better performance readability, assessed by state-of-the-art
readability models. Our results provide initial evidence that CDD
could be an interesting approach for software design