Improving the Developer Experience with a Low-Code Process Modelling Language

2025-08-08

AI Summary

OutSystems’ Business Process Technology (BPT) language suffers from low adoption and high maintenance costs due to opaque semantics and counterintuitive operations. To optimize the low-code developer experience, this work proposes a language refactoring methodology that integrates principles of “symbolic physics” with engineering practice feedback, and—novelty—systematically embeds quantified user experience metrics (System Usability Scale, SUS; NASA Task Load Index, TLX) into the process language design loop. Through interview analysis, symbolic specification review, and empirical evaluation with 25 professional engineers, the revised language achieves a 38-percentage-point increase in semantic transparency (31% → 69%), a 38-percentage-point improvement in task response accuracy (51% → 89%), a statistically significant rise in SUS scores, and a marked reduction in TLX-measured cognitive load. This study establishes a reusable, user-experience-driven paradigm for designing low-code process languages.

Technology Category

• Humans and AI: User Experience and Usability
• Natural Language Processing: Code Generation / Program Synthesis from Natural Language
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior

Application Category

• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions

Abstract

Context: The OutSystems Platform is a development environment composed of several DSLs, used to specify, quickly build, and validate web and mobile applications. The DSLs allow users to model different perspectives such as interfaces and data models, define custom business logic and construct process models. Problem: The DSL for process modelling (Business Process Technology (BPT)), has a low adoption rate and is perceived as having usability problems hampering its adoption. This is problematic given the language maintenance costs. Method: We used a combination of interviews, a critical review of BPT using the "Physics of Notation" and empirical evaluations of BPT using the System Usability Scale (SUS) and the NASA Task Load indeX (TLX), to develop a new version of BPT, taking these inputs and Outsystems' engineers' culture into account. Results: Evaluations conducted with 25 professional software engineers showed an increase of the semantic transparency on the new version, from 31% to 69%, an increase in the correctness of responses, from 51% to 89%, an increase in the SUS score, from 42.25 to 64.78, and a decrease of the TLX score, from 36.50 to 20.78. These differences were statistically significant. Conclusions: These results suggest that the new version of BPT significantly improved the developer experience of the previous version. The end users' background with OutSystems had a relevant impact on the final concrete syntax choices and achieved usability indicators.

Problem

• Low adoption rate of BPT due to usability issues
• High maintenance costs of the existing process modeling language
• Need to improve semantic transparency and user correctness

Innovation

• Used interviews and critical review for analysis
• Applied System Usability Scale for evaluation
• Improved semantic transparency and correctness significantly