Your position
In this PhD project, you will assess the statistical validity of psychological intervention studies. You will apply a wide range of state-of-the-art meta-scientific techniques to studies in the domain of medical and clinical psychology. Your project can have immediate impact by proposing concrete ways to improve practices in psychological intervention studies. This interdisciplinary PhD project lies at the intersection of methodology and statistics on the one hand, and medical and clinical psychology on the other hand. A rough outline of the project would entail:

Project 1: Conduct a systematic review describing often used analysis models testing psychological interventions and if/how flexibility in data analysis is prevented in accompanying preregistrations.
Project 2: Run simulation studies to assess whether the models found in Project 1 provide unbiased estimates of a true intervention effect and whether power analyses with these models would result in substantially different minimum sample sizes than the required sample size reported in the studies from Project 1 .
Project 3: Assess the effect of statistical variability of (un)published intervention effects in practice, by re-analyzing all available data on a specific psychological intervention of your own choosing.
Project 4: Synthesize the findings of projects 1 and 3 by providing a set of guidelines to increase the statistical validity of psychological intervention studies.
You are encouraged to make this research your own, by choosing your own specific focus and project implementations. We highly value your input and creativity.
 

Research context
You will work under direct supervision of dr. Paul Lodder, dr. Michèle Nuijten,  and prof. dr. Jelte Wicherts .You will be part of the Meta-Research Center (https://metaresearch.nl), a renowned research group working on a variety of topics within meta-research in psychology (i.e. publication bias, meta-analysis, causal inference, p-hacking, preregistration, qualitative research). You will have ample opportunity to collaborate within the research group, and you are encouraged to seek collaborations outside the Meta-Research Center as well, for example with the department of Medical and Clinical Psychology.

Your assessment of the statistical analysis of psychological interventions can have direct impact on the way researchers analyze intervention effects in psychology. You are encouraged to actively share your findings and recommendations through scientific papers and conferences, but also through channels such as blog posts, social media, and news outlets. 

We strongly value open science: among other things, we encourage preregistration, sharing of data and materials, and we facilitate open access publication.
Beside research, you will also contribute to the teaching tasks within the department. 

Background
Myriad studies in medical and clinical psychology investigate the effectiveness of psychological interventions in improving the mental health of patients with various physical diseases or mental disorders. Despite the fact that researchers testing psychological interventions are generally interested in similar research questions (i.e., is intervention A more effective than intervention B in improving mental health?), they can answer them using a wide range of methodological designs of varying quality. Even the methodological gold standard of intervention research, the randomized controlled trial, can be threatened by the “degrees of freedom” researchers have when analyzing their data. For most published intervention studies it remains unclear whether different statistical models would have produced similar conclusions. In this PhD project, you will aim to answer this question.

We have the following requirements:

• A (nearly finished) (Research) Master’s degree in psychology or a related field
• A strong background in methodology and statistics
• Experience with programming
• Excellent communication skills (e.g., the ability to clearly communicate complex statistical findings to non-experts)
• Tilburg University is an international university, firmly rooted in the region and therefore bilingual. We expect our employees to meet the language level appropriate for the position. For academics, an excellent command of English is required: CEFR level C2.

Fixed-term contract: 4 years.

This is a position for 1.0 FTE (40 hours per week) of the full-time working week. 
The salary amounts to a minimum of €2.541 and a maximum of €3.247 gross per month for full time employment contract, based on UFO profile PhD student and salary scale number PhD’s of the Collective Labour Agreement for Dutch Universities. Tilburg University uses a neutral salary system for scaling that is based on relevant education and work experience. 

You are entitled to a vacation allowance of 8% and a year-end bonus of 8.3% of your gross annual income. If you work 40 hours per week, you will receive 41 paid days of leave per year.
Tilburg University offers excellent employment conditions. We think flexibility, professional and personal development, and good employee benefits important. We make clear agreements about career paths and offer all kinds of facilities and schemes to maintain an optimal balance between work and private life. You can also follow numerous training courses, for example in the areas of leadership skills, personal effectiveness, and career development.  

Tilburg University values an open and inclusive culture. We embrace diversity and encourage the mutual integration of groups of employees and students. We focus on creating equal opportunities for all our employees and students, so that everyone feels at home in our university community.
Tilburg University has a lively campus in beautiful green surroundings that is easily accessible by public transport. We are committed to a sustainable society and challenge you to make an active contribution.

Please visit working at Tilburg University for more information on our terms of employment. 

Tilburg University

Serving society and making it better for its citizens. That is what drives us. Tilburg University's founder, Martinus Cobbenhagen, believed that anyone who wants to understand society must be actively and consciously involved in it. These ideas still form the basis of our university.
Under the motto Understanding society, our more than 2,800 employees develop and transfer knowledge and bring people from different disciplines and organizations together. In this way, we want to contribute to solving complex social issues. In doing so, we work from the fields of economics, business and entrepreneurship, social and behavioral sciences, law and administration, humanities and digital sciences, and theology.

We educate our 20,000 students of 132 nationalities to become Tilburg University Shaped Professionals: responsible and entrepreneurial thinkers, driven by solidarity, a sense of responsibility and empathy, who are able to influence and give direction to a rapidly changing society in an innovative way.