A master’s thesis, carried alone
My master’s thesis in Digital Design at HdM Stuttgart, submitted on 31 March 2025 and carried out alone: research, interviews, taxonomy, concept, interface, build and evaluation. Full title: Development of a Context-Specific Usability Framework for the Multidimensional, Care-Needs-Oriented Usability of Digital Care Applications.
credits
Four experts, one standard, twelve dimensions
The work combined literature research on home care, DiPA regulation, usability and accessibility with an analysis of the BfArM approval process and four expert interviews, spanning product strategy and mHealth infrastructure, UX design for regulated health products, and professional home care. From that I built a taxonomy, designed and developed the artefact, and evaluated it with five participants using Likert-scale questions and the UEQ-S.
Orientation instead of recommendations
The first concept was an input-output tool: describe your planned DiPA, receive tailored usability recommendations. I dropped it. The context is too complex for a recommendation engine to be honest at thesis scale, and the thesis had no way to validate what such a tool would output. The artefact became a structured interactive visualisation that helps a team understand the context and draw its own conclusions. Its authority rests on sourced structure that a reader can check.
voices
Three tensions ran through every interview: regulation small companies cannot navigate, target groups too heterogeneous to design for as one, and tools that only create value if they fit care routines without interrupting trust or communication.
The 3D version was accurate and unusable
The first visualisation was three-dimensional, on the reasoning that a multidimensional subject deserves a multidimensional picture. It failed on all three counts that mattered: usability, responsiveness and readability. I replaced it with a flat two-dimensional structure. The complexity belongs in the content, and the picture’s job is to make it walkable.
Built on the standard the regulator already cites
The taxonomy takes the four context components of ISO 9241-11, users, tasks, tools and environment, and adds two hierarchy levels, producing twelve DiPA-specific dimensions: user constellations, combined barriers, care level, sociodemographics, technology acceptance, area of care benefit, subarea of care systematics, application type, physical-spatial context, home environment, care network, technical infrastructure. That way the framework speaks the language of the standard the approval process already references.
craft
Built to be read
Inter for reading, Space Mono for structure. A bright, minimal interface. Dark mode was built and discarded because it cost readability across the longer explanatory passages. Every dimension carries its sources as links, hover states hold the second layer of each graphic, and the information architecture is modular so the map can grow into a broader DiPA knowledge base.
outcome
Tested before it went up
It was tested before it went up. Five participants worked a scenario: UX designer at a fictional manufacturer turning a sensor mattress for care homes into a certified DiPA, with ten minutes on the map to identify a persona and an application type. Four of the five gave the highest available rating on both knowledge-transfer questions, covering a better understanding of what a DiPA is and what it has to fulfil, and help in grasping and applying their own product’s usage context. The UEQ-S came out at 0.975 overall, with pragmatic quality at 1.275 and the single item supportive at 2.1.
results
4 OF 5 gave the highest rating · 0.975 UEQ-S overall · 2.1 item: supportive
live
THE MAP IS LIVE
Everything above is the road to it. The map itself is a website, and reading about an interactive artefact is a poor substitute for using one. Twelve dimensions, each with its sources attached, built to be walked through.
learnings
What the same numbers say against it
Hedonic quality landed at 0.675, upper neutral, and the items original and novel both scored exactly 0.0. The map earns its keep as a reference and leaves people cold. Navigation split the group: two found it intuitive, one agreed, one was neutral, one disagreed outright, so the artefact explains well and guides unevenly. Five participants is a small sample. The thesis timeframe was enough to identify all of this and too short to run another iteration, which is exactly where I would start.