Maarten Krol Numbers telling the tale? On the validity of patient experience surveys and the usability of their results

Date of PhD graduation:   June 12, 2015
Institute: Netherlands institute for health services research (NIVEL)  
 Supervisor:  Prof. Diana Delnoij
 PhD  Co-supervisors:  Dolf de Boer, PhD and Jany Rademakers, PhD
Subject of the thesis

In the past decades, patient experiences have become an important source of quality of care information. In Dutch health care, where a system of regulated competition is in place, this information is used not only by patients, but also by health care providers and health care insurers. Because of this, the validity of patient experience surveys must be thoroughly substantiated. In my doctoral thesis, I have attempted to show how important it is to examine the answers and the relationships between them in order to understand the consequences of tailoring a questionnaire.

Although a valid patient experience questionnaire measures aspects of health care relevant for all concerned parties, it particularly measures those aspects that are relevant for patients. Various methods are used to involve patients in the process of developing and tailoring these questionnaires. In my thesis, I have researched the use of single items to summarise patient experiences and whether these items are a valid representation of the wide array of patient experiences that are gathered. For instance the way patients think they were dealt with by health care providers, the information they received, but also the results of a treatment. In this respect, both Patient Reported Experience Measures (PREMs) and Patient Reported Outcome Measures (PROMs) have played an important part in my doctoral research.

Main conclusions

There is a desire to use single questions or items to summarise patient experiences and satisfaction – for instance, a rating, or whether a patient would recommend the health care provider. However, such a question needs to sufficiently reflect the individual experiences reported by patients. Early on in every study, determine for whom the results are relevant and how to best present them. Detailed information can be interesting, but may also be confusing. And a summary may be useful, but can lead to an oversimplified version of reality. One size fits all’ doesn’t apply here, and presenting quality of care information remains a balancing act.

Obtaining my PhD

The process of obtaining my PhD has been a bit out of the ordinary, because of the fact that I worked on several research projects that were not linked to my doctoral thesis. This had both drawbacks and advantages. On the one hand, the ‘normal’ work sometimes took up all of my time and focus,  leading to a delay of my doctoral research. On the other hand, the fact that I could work on other projects aside from my PhD thesis was often refreshing. It meant getting to know and working together with many other interesting people and organisations. To my opinion, the first stages of my PhD program were the most difficult, because I started from scratch with a somewhat vague notion of a subject for my doctoral thesis. But due to the fine support from my (co)supervisors and the acceptance for publication of the first two research papers, it really felt like I was getting somewhere. In the summer of 2014, knowing that I was close to finishing my doctoral thesis provided a major motivational boost. Being able to finally put all the pieces of the puzzle together to produce the actual thesis was the most gratifying stage of my PhD programme. Although this was a process of almost endlessly changing and shifting paragraphs and sections, it felt great to be able to finally submit the manuscript to the university.

The graduation day itself was a strange, but beautiful day. Having the beadle step onto the stage and hearing him say the words ‘Hora est’, after an hour of defending my thesis, meant a sudden end to my four year PhD programme. It was really special to share this day with my wife, family, friends, (co)supervisors and colleagues.



After PhD graduation

A few months before my actual graduation date, I had already started working as a research consultant at VGZ, a major Dutch health insurance company. The main focus of my work is how to use information on quality of care in purchasing health care and to research the opinions and experiences of enrolees with the service of both VGZ and health care providers.