Axel Budde

Axel Budde

Patient-Centered Outcomes Researcher & Clinical Data Scientist

Biography

Psychologist (M.Sc. Hons, University of Amsterdam) with seven years of clinical research experience across oncology, palliative care, and public health. Specialising in patient-centred outcomes, psychometric validation, and clinical data science. PhD candidate at the University of Bonn, Faculty of Medicine (Epidemiology): machine-learning prediction of quality of life after childhood cancer.

I have published on COA instrument harmonisation — linking paediatric and adult patient-reported outcome measures in an international osteosarcoma cohort (European Journal of Cancer, 2022) — and have a manuscript in preparation on non-response prediction in childhood cancer survivor surveys using machine learning.

On the applied side, I build R Shiny tools that make complex statistical methodology accessible to clinical researchers, including a psychometric analysis tool for IRT-based item fit evaluation and a dashboard developed for the Lancet Commission on Palliative Care and Pain Relief.

Download my CV.

Interests
  • Patient-Centered Outcomes Research
  • Psychometrics & COA Validation
  • Clinical Data Science
  • R & R Shiny Development
Education
  • PhD Candidate in Epidemiology (expected completion: 2027)

    University of Bonn, Germany

  • MSc in Psychology (With Honours), 2004

    University of Amsterdam (UvA), The Netherlands

  • Diploma in Criminal Science, 1997

    University of Pau and Adour Countries (UPPA), Pau, France

Skills

R & R Shiny
Psychometrics & COA
Clinical Data Science
SQL

Recent Projects

 
 
 
 
 
FUN For Fit – Psychometric Analysis Tool
January 2025 – Present

Evaluating the practical significance of item misfit in psychological and educational tests (axelbudde.shinyapps.io/FUNForFit)

  • Rasch model (1PL) and 2PL IRT analysis of weighted MNSQ fit statistics – methods central to Clinical Outcome Assessment (COA) validation
  • 2D IRT modelling to estimate correlation bounds after Köhler & Hartig (2017)
  • Step-guided interface with interactive result visualisation (Plotly)
 
 
 
 
 
SHS World Map – Interactive Dashboard
February 2023 – December 2025

Global visualisation of Serious Health-Related Suffering (SHS) burden data (Live dashboard) – developed for the Lancet Commission on Palliative Care and Pain Relief

  • Patient-centered epidemiological endpoint: SHS operationalises unmet need for palliative care across 195 countries
  • Interactive maps, time series charts, and hierarchical visualisations
  • Responsive web dashboard with complex filtering for research and advocacy audiences
 
 
 
 
 
R Shiny Project
Routing Ruler – SaaS Rule Compliance Application
October 2024 – Present

Commercial freemium SaaS application for airline fare routing rule analysis (routingruler.com)

  • Parses complex, heterogeneous rule sets from multiple industry data sources (ExpertFlyer, KVS Tool, Amadeus GDS)
  • Multi-dimensional constraint logic across stopovers, transfers, IATA geographic zones, and carrier restrictions
  • EgoTrip mode for instant rule-compliance verification; carrier and alliance filtering
  • Full end-to-end product ownership: algorithm design, development, deployment, and commercial subscription management

Experience

 
 
 
 
 
Routing Ruler
Independent Research & Development
October 2024 – Present Germany
Independent research & development (concurrent with parental leave). Primarily development of Routing Ruler, a commercial SaaS application for airline fare routing rule analysis (R Shiny).
 
 
 
 
 
Charlotte Fresenius University of Psychology
External Lecturer
October 2023 – September 2024 Düsseldorf, Germany

Lectures in Psychology degree programme (B.Sc.):

  • Introduction to psychology and its history
  • Research methods
  • Psychotherapy
 
 
 
 
 
University Hospital Bonn (UKB) Clinic for Palliative Medicine
Research Associate
February 2023 – September 2023 Bonn, Germany

Development of R Shiny app for visualisation of Serious Health Related Suffering (SHS):

 
 
 
 
 
University Hospital Bonn (UKB) Network University Medicine (NUM), Institute for Virology
Head of Local Staff Unit
October 2020 – December 2022 Bonn, Germany
Coordination of Local Staff Unit in Network University Medicine
 
 
 
 
 

Coordination of project “E-Surv” (Funding: German Cancer Aid):

  • Randomised study (n = 2,000, German Childhood Cancer Registry) comparing paper-based and eCOA administration of validated PRO instruments including EORTC-QLQ-C30, SF-36, and Multidimensional Fatigue Inventory — a direct eCOA mode equivalence study
  • Logistic regression modelling of response rate predictors (sex, socioeconomic deprivation, time since diagnosis)
  • Metadata harmonisation across multiple paediatric oncology studies (COSS, CESS, CWS) using Samply.MDR metadata repository

Graduate programme “Epidemiological Research Using Cancer Registry Data” (German Cancer Aid):

  • July - August 2019: University of Mainz, German Childhood Cancer Registry – Comparative non-response analysis
  • January - February 2019: University of Bern, Switzerland, Institute of Social and Preventive Medicine (ISPM), Paediatric Cancer Epidemiology Group (Prof. Dr. Claudia Kühni) – Development of Shiny app for space-time analyses of Swiss Childhood Cancer Registry data
 
 
 
 
 
Axel Budde
Advanced training “Mastering Software Development in R Specialization” and self-employment
January 2017 – May 2018 Cologne, Germany

Developed R Shiny apps:

 
 
 
 
 
  • Coordination of federal-state network for online documentation system Dot.sys
  • Coordination of federal-state network for relaunch PrevNet/Inforo online
  • Coordination of EU project “Reducing Alcohol Related Harm” (RARHA) (Work Package Co-Lead)
  • Representation within German Monitoring Centre for Drugs and Drug Addiction (DBDD) and vis-à-vis European Monitoring Centre on Drugs and Drug Addiction (EMCDDA)
 
 
 
 
 
Boutique air travel agency Airotique
Self-employment
Boutique air travel agency Airotique
March 2011 – February 2013 Berlin, Germany
 
 
 
 
 
Noldus Information Technology GmbH
Regional Sales Engineer
November 2006 – July 2007 Berlin, Germany
Sold software for behavioural research and gave product trainings.
 
 
 
 
 
Noldus Information Technology bv
Regional Sales Engineer
November 2005 – October 2006 Wageningen, The Netherlands
Sold software for behavioural research and gave product trainings.
 
 
 
 
 
Citicorp S.A.
Customer Service Representative
March 2005 – July 2005 Barcelona, Spain
Provided phone service to credit card clients in Belgium in Dutch, French, German, and English.

Technical Skills

Programming

  • R (daily since 2017 – expert)
  • R Shiny (daily – expert)
  • SQL (often), LaTeX (often), R Markdown (often)

Outcomes Research & Psychometrics

  • Clinical Outcome Assessment (COA) instrument analysis
  • Item Response Theory (IRT): Rasch / 2PL models (TAM package)
  • Patient-Reported Outcome (PRO) / eCOA methodology
  • Survey mode effects, non-response analysis
  • Psychometric validation (fit statistics, reliability, validity)

Statistics & Data Science

  • Hypothesis testing, KPI development, data cleaning
  • Reproducible workflows, machine learning (random forests, penalised regression)

Documentation & Reporting

  • R Markdown (expert), LaTeX (often), Git/GitHub (proficient)

Cloud & Deployment

  • Render (daily), Supabase (often), AWS (often)

Additional Tools

  • Metadata database MDR.Samply (often)
  • SaTScan (often), QGIS (rarely)
  • MySQL (often)

Languages

  • English – Business fluent, IELTS (Academic) Band 8.5/9
  • Dutch – Business fluent
  • French – Fluent
  • Spanish – Advanced basics
  • German – Native

Scholarships

Travel Scholarship
Travel scholarship for poster presentation of preliminary findings from “Linking EORTC QLQ-C30 and PedsQL/PEDQOL physical functioning scores in patients with osteosarcoma” at the North American Symposium on Late Complications After Childhood Cancer, Atlanta, Georgia, USA
Travel Grant
Travel grant for poster presentation of preliminary findings from “Linking EORTC QLQ-C30 and PedsQL/PEDQOL physical functioning scores in patients with osteosarcoma” at the North American Symposium on Late Complications After Childhood Cancer, Atlanta, Georgia, USA
International Internship Scholarship
Short scholarship for internships in international organisations. United Nations Office on Drugs and Crime (UNODC), Regional Centre for East Asia and the Pacific, Bangkok, Thailand
Study Visit Scholarship
STUNT scholarship for study visit to Xiamen University, Xiamen, People’s Republic of China
Supplementary Study Visit Scholarship
Supplementary scholarship for study visit to Xiamen University, Xiamen, People’s Republic of China

Specialisation

Coursera
Building Data Visualization Tools by Johns Hopkins University on Coursera
See certificate
Coursera
Building R Packages by Johns Hopkins University on Coursera
See certificate
Coursera
Advanced R Programming by Johns Hopkins University on Coursera
See certificate
Coursera
The R Programming Environment by Johns Hopkins University on Coursera
See certificate

Projects

*
FUN For Fit
Psychometric analysis tool for evaluating item misfit in psychological and educational tests using IRT methods.
Routing Ruler
Commercial SaaS application for airline fare routing rule analysis — end-to-end product built in R Shiny.
SHS World Map
Interactive global dashboard visualising Serious Health-Related Suffering burden data, developed for the Lancet Commission on Palliative Care and Pain Relief.

Gallery

Recent Publications

Quickly discover relevant content by filtering publications.
Estimates of protection levels against SARS-CoV-2 infection and severe COVID-19 in Germany before the 2022/2023 winter season: the IMMUNEBRIDGE project
Despite the need to generate valid and reliable estimates of protection levels against SARS-CoV-2 infection and severe course of …
SARS-CoV-2 sero-immunity and quality of life in children and adolescents in relation to infections and vaccinations: the IMMUNEBRIDGE KIDS cross-sectional study, 2022
The study evaluates the effects on sero-immunity, health status and quality of life of children and adolescents after the upsurge of …
Grundimmunität gegen SARS-CoV-2 in der deutschen Bevölkerung
Hintergrund: Während der SARS-CoV-2-Pandemie wurden in einigen Ländern von Beginn an nationale populationsbasierte Seroprävalenzstudien …
Estimates of protection against SARS-CoV-2 infection and severe COVID-19 in Germany before the 2022/2023 winter season - the IMMUNEBRIDGE project
Despite the need to generate valid and reliable estimates of protection against SARS-CoV-2 infection and severe course of COVID-19 for …
Erratum to ‘Linking EORTC QLQ-C-30 and PedsQL/PEDQOL physical functioning scores in patients with osteosarcoma’ [Eur J Cancer 170 (2022) 209-235]