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The Client

DasTelefonbuch Servicegesellschaft mbH, Frankfurt, Germany

The first German White Pages phone book was printed 135 years ago. Despite the recent competition with Google, 10.9 million unique users / month make and its mobile app to one of today's most important Internet offerings in Germany. The services are offered by the Das Telefonbuch-Servicegesellschaft mbH in Frankfurt, Germany.

Project Synopsis

They are my longest-term clients. Over the last 9 years me and my company ran several projects in 3 categories with them: User Research , UX Design Audits ("Expert Analysis") and UX Design. All of them included UX Consulting.


  • Private and business contact search portal on desktop (Win) and mobile (Android) devices
    • Front page = search interface
    • Result list
    • Result detail pages
    • "Mein Telefonbuch" customer self-service area
  • DasTelefonbuch app (Android)

My Responsibilities

  • Selection of appropriate research methods and user testing tools
  • Use of business requirements, Usability findings and market research to develop user test scenarios, use cases and high-level requirements
  • Evaluation and of suitable quantitative Remote Web User Testing tools
  • Quantitative Remote Web User Testing survey design, implementation & analysis
  • To conduct Usability Lab Tests, Eye Trackings, quantitative Remote Web Usability Studies, Cognitive Walkthroughs and Heuristic Analysis across devices
  • German test participant profiling and recruitment
  • Definition of meaningful UX metrics to evaluate the objective and subjective test user experience
  • Usability Lab Test facilitation
  • Development of hands-on design and usage process flaw fixes based on UX Design best practices
  • Application of strategic thinking to UX Design combining design best practices with tangible user + business goals while keeping technical realities in mind
  • Visualization and communication of UX Design concepts to board members supporting the process of mutual agreement to changes I recommended
  • Responsive HTML prototype creation in Axure RP Pro, including subsequent user testing
  • Image processing and modification
  • Back-reporting of test results to Product Managers, Developers and Designers
  • Development and provision of thought leadership in the search site and app UX Design and User Experience across devices
  • Active support of Designers and Product Managers on tangible design and process improvements by planning and conducting Design Optimization Workshops
Ralph and his Usability People team enabled us to gain deep insights into the hearts and minds of our users. A/B testing alone was not able to creat such an in-depth understanding of our users.

Frank Gondorf, CEO,


  • Establishment of Heuristic Analysis, Cognitive Walkthroughs and software-based Eye Tracking simulation as low-resource, high-impact user testing methods
  • Verification of qualitative UX testing results validity by identifying and implementing Remote Web User Testing with 1000 monthly test participants as a means of deep-insight quantitative testing
  • Presenting results and mediating discussions on Board Management level


  • Despite the heavy competition with Google remains in business
  • 8.486 users rate the DasTelefonbuch app with 4 out of 5 stars in Google Play Store
  • 95 percent of are satisfied with the results searching for a commercial provider
  • An average of 52% of the German online population knows