Realizing MDE using Projectional Language Workbenches

Quick Link: The online appendix to our paper "Efficiency of Projectional Editing: A Controlled Experiment" is available in the document online appendix.pdf at the bottom of this page, together with other material.


This page provides supportive quantitative and qualitative data for our study on the editing efficiency of projectional workbenches. The project is a collaboration between Thorsten Berger (Chalmers | University of Gothenburg, Sweden), Markus Voelter (independent/itemis, Germany), Janet Siegmund (University of Passau, Germany), Hans Peter Jensen and Taweesap Dangprasert (IT University of Copenhagen, Denmark), and Bernd Kolb (itemis, Germany).

Project Description

Projectional language workbenches, such as the Jetbrains Meta Programming System (MPS), follow a radically different approach to programming and model-driven development. They allow almost unlimited language composition and the use of a diversity of notations -- by using an editor that does not rely on parsers, but directly modifies the abstract syntax tree (AST) of a program or model.

Goal and Method

The goal of this project is to investigate the effects of projectional editing in the context of common programming and professional large-scale industrial engineering efforts. Our methodology is three-fold: (1) We analytically derive usability issues following from architectural differences between projectional and parser-based editors, and map these issues to MPS/mbeddr's mitigation techniques. (2) We survey professional developers to understand the effectiveness of these mitigations. (3) We conduct a controlled experiment to measure the effects of projectional editing on editing efficiency, editing strategies, and kinds and rates of errors. In this controlled experiment, we also identify hotspots that need to be addressed/improved to sustain projectional editing, and compare projectional editing to parser-based editing.


This page contains a replication package (online appendix.pdf, repo-Proj,, for our controlled experiment belonging to the paper "Efficiency of Projectional Editing: A Survey, an Experiment, and Lessons Learned" (under review).

This page also contains supportive data about the preparatory questionnaire we used to survey professional developers who have used MPS. The file attachments below comprise the questionnaire (questionnaire.pdf) and statistics about the responses (survey-report.pdf).


online appendix.pdf989.34 KB
repo-Proj,ProjE.zip161.13 KB
repo-Par.zip21.52 KB
questionnaire.pdf55.23 KB
survey-report.pdf87.55 KB