Into the QOL-verse: A Reflection on Quality of Life Valuation Origin Stories
Written by: Caitlyn Solem
Just a few musings before ISOQOL from your friendly neighborhood Patient-Centered Outcomes researcher.
Thanks to COVID-19 we have instituted a family movie night at my house on Fridays. With 4 and 6-year-old children, this has exposed me to a diverse range of movies. One of these that I actually found really enjoyable was “Spider Man: Into the Spider-verse” which, if you haven’t seen it (spoiler alert), involves a number of parallel realities coming together and dropping versions of Spider-Man in one reality, where they come together to mentor Miles Morales, who is also bitten by a radioactive spider and is new to his power.
As I get ready to attend ISOQOL 2020 online, this got me reflecting on the different ‘origin stories’ of different branches of health-related quality of life valuation across the field. I will not claim to be a top expert in any of these areas but have had a smattering of exposure to different camps over my career, so please feel free to comment or add if you view differently!
We have the classical test theory camp, who are looking at the reliability and validity of measures from a practical and pragmatic perspective, understanding whether a scale or set of scales (often with each scale being made of multiple items) is working as intended and evaluating the accuracy and repeatability of measurement. This to me would probably be represented by the alternate universe, slightly more world-worn Peter B Parker Spider Man who takes the lead on training Miles. A simple summary score works and gets us to an overall dimension-level (and sometimes total) score at the end of the day.
Then we have the new(er) kids on the block, the item response theory crowd, who are add the nuance that not every item is the same difficulty, and that placing items on a harmonized scale and understanding the true underlying structure provides a better calibration. This is probably Gwen Stacy- the smart and lovable Spider-Woman character who also plays a core role in helping Miles come to terms with his powers (which, in my extended analogy, is of course how to ‘best’ measure and summarize health-related quality of life). For this camp, you often get a score on a norm- referencing scale, although not everyone quite fully understands how what you put in leads to where you come out.
Finally, we have the preference camp, looking typically for a set of single-item dimensions that have been derived from an entirely different perspective: how do we value the quality of life benefits of a particular treatment in a way that reflects the value placed on each item by members of a particular group (often from a societal perspective)? Given these are coming from a completely different framework, I will just put this one as Spider-Man Noir, or perhaps Peni-Parker with her anime and biomechanical suit (which, of course, would be the value sets for the preference measures).
It is very interesting to me that while each of these different perspectives has its own origin story and motivations, representatives of these fields are all able to converge at conferences like ISOQOL and truly think about how we use our combined powers for good to train the next Miles, who (at least in the movie) learns a bit from all to develop his own unique style. I see this playing out in initiatives like personalized utility functions which combine the elicitation of values used by preference measures with the potential to be applied to represent revealed perceptions of ‘item difficulties’ at a patient level, similar to the item response theory crowd. Or perhaps it will be the novel approaches to measurement of change over time. Regardless, it is an exciting time in the field, and good for all of us to remember as researchers “with great power comes great responsibility!”