BWS correct referencing redux

This is not exactly a moan (since in some cases I’m requesting fewer references to one or two of my own papers, which is all very nice!). It’s just a reminder that BWS has been an evolving technique over many years and I continue to note too many people just seem to add the JHE 2007 paper as “the BWS reference” when it really isn’t supporting what they are doing or saying.

I’m not been afraid to admit when I’ve done something incorrect/misleading, or when the field has moved on and an earlier paper is becoming outdated. (So when I call others on bad referencing, rest assured that I do the same for myself.)

Some points to note:

  • The JHE article was the first comprehensive explanatory Profile Case (Case 2) BWS paper. However, the “marginal models” there involved coding that although gives correct point estimates, give misleading summary statistics like log-likelioods, by not taking account of the sequential nature of the data. Thus, a choice from 5, means only 4 options are available for the second choice.
  • This was corrected ASAP – the 2008 BMC paper on dermatology study corrected this, so marginal sequential models should really reference this paper.
  • References to “dual/multi stage choice tasks” (primarily to get QALYs) should start with my 2010 Pharmacoeconomics paper, since that was the first to propose these (including the DCE+TTO rescaling) method. Too many researchers reference later papers.
  • I was also first in explaining why the “death state” can’t be valued in a DCE without duration and a higher resolution design – in 2008 I wrote about this in Pop Health Metrics, with the God of math psych, Tony Marley, amongst others. I also pointed out why variance scale factors can be highly problematic in DCEs/other choice models. I certainly wasn’t first on the latter point – you should be looking to papers in the 1990s by Swait & Louviere, and Hensher and Louviere for that.
  • First reference to a Case 1 BWS study is in The Patient: Patient-Centered Outcomes Research (2010) by Louviere and Flynn (to my knowledge – I am happy to be corrected if wrong).
  • If you’re comparing Case 2 BWS with DCEs you really should be understanding and discussing how they differ, which was introduced in detail in the 2013 JoCM paper by Flynn et al. Subsequent discussion in the book (2015). DO NOT conclude that either method is “wrong”/”right” purely on basis of comparison of results from each task. Our work explains why they might differ.
  • For Case 3 BWS I’m not the key person, Emily Lancsar was/is big in introducing and applying this in health. Please also note the correct name for this is the “multi-profile case” as agreed by Louviere, Marley and me in preparation for the book. Like the profile case, renaming was done so as to better describe what made Cases 2 and 3 distinct from other Cases.
  • First reference to a peer-reviewed published Case 2 study was from the 1990s by Szeinbach et al; first UK study was 2006 by our team in BJD.
  • Finally, the emerging problems with highly efficient designs: Rose and Bliemer hypothesised this back in 2009; I and team published the first within-subject confirmation in Pharmacoecon 2016.

Thus, it’s just a guide to help practitioners get the correct reference for BWS and associated conceptual issues. Hope it helps. I may add to this if I think of other issues that are incorrectly attributed.