Wednesday, 17 September 2014

BCEA 2.1

We're about to release the new version of BCEA, which will contain some major changes.

  1. A couple of changes in the basic code that should improve the computational speed. In general, BCEA doesn't really run into troubles because most of the computations are fairly easy. However, there are a couple of parts in which the code wasn't really optimised; Chris Jackson has suggested some small but substantial modifications $-$ for instance using ColMeans instead of apply($\cdot$,2,mean)
  2. Andrea has coded a function to compute the cost-effectiveness efficiency frontier, which is kind of cool. Again, the underlying analysis is not necessarily very complicated, but the resulting graph is quite neat and it is informative and useful too.
  3. We've polished the EVPPI functions (again, thanks to Chris who's spotted a couple of blips in the previous version).
I'll mention this changes in my talk at the workshop on "Efficient Methods for Value of Information Calculations". If all goes to plan, we'll release BCEA 2.1 by the end of this week.

Monday, 8 September 2014


This is an old story (it dates back to July last year) but it just got under my radar and I think it's quite unbelievable $-$ or may be it isn't after all... 

In a survey of just over 1000 individuals developed by professional company Ipsos Mori, respondents were asked to give their opinion on a series of "urban myths" (as it turns out). 

For example, the perception of the surveyed sample on benefit fraud is way out of line ("the public think that £24 of every £100 of benefits is fraudulently claimed. Official estimates are that just 70 pence in every £100 is fraudulent - so the public conception is out by a factor of 34", as the Independent article puts it).

Other topics on which the public seems to have a very biased opinion are immigration (with 31% of the population believed to have recently migrated into the UK, while the official figure is actually around 13%) and teen pregnancy (perceived to be 25 times as prevalent than it actually is!). That'll make for a nice example in my course on Social Statistics...

B my J

As part of our work on the Regression Discontinuity Design for the British Journal of Medicine, we decided we should prepare a short, introductory research paper. We weren't holding our breath, as we thought that, while obviously interesting to clinicians, the topic may be a little too complex and technical for the BMJ audience. So we tried really hard to strip it out of the technicalities to highlight the substantial points $-$ which they liked! 

The paper was reviewed rather quickly and the comments were positive (although iI remember thinking that there was a sense of "you need more, but also much less" (which reminded me of Jeremy from Peep Show)... 


Anyway, they seem to have liked the revisions too and the paper is now out.

Thursday, 4 September 2014

No surprises

Yesterday was the day of my talk at the RSS Conference. As I mentioned here, I hadn't been back to Sheffield for nearly 20 years, so it is really no no surprise that I found it reeeeally (I mean: really) changed. In fact, I think I'm being a victim of some confounding here $-$ not sure of quite as much of how I thought things changed is due to the fact they have really have changed or rather to the fact that I have changed, since then...

Back then, in the 18th century, it was my first time outside Italy, so everything was new and unfamiliar, although I seem to remember that there really was no proper coffee place (or just coffee to be had), outside an eight-decent French place... Also, while I distinctly remember enjoying being there, I couldn't really, fully recognise the streets I was walking (even if I'm sure I had walked along them before). So I suppose the place must be changed indeed!

The talk went well (the file is large, because of the couple of maps I've included $-$ but I thought they looked nice, so I left them in). I joked around a bit $-$ it wasn't difficult, given the topic. I made the point that it's not time to panic and leave the EU, just yet, at least not on account of the fact that the Eastern European countries hate the UK and thus do not vote for them in the Eurovision.

On other news, I really liked Tim Harford's talk $-$ it was funny and it told a very nice story, which is good. He gave a couple of more or less (pun intended) known examples of "big" (or, as he also put it, "found") data leading to some undesirable results and made the general argument that we shouldn't really dismiss the core of statistical methodology, just because we can get a lot of data and we can deal with them. How to not agree?

Wednesday, 27 August 2014


Next week I'm off to the RSS conference in Sheffield, where I'll present our work on the Eurovision contest. I'm quite excited about going back to Sheffield, where some time in the last century, I've spent a semester as an Erasmus Exchange student. In fact, this will be the first time I'm back since then $-$ I've spoken with a few friends who tell me that the city has changed so much in the last few years, so I'm curious to see what I'll make of it. 

 I have fond memories of my experience and I'm very glad I've taken that opportunity (although at the time the exchange rate between Italian Lire and the Pound was 2 million to 1...). In particular, I'm glad I got to be at one of the last editions of the Pyjama Jump!   

Wednesday, 20 August 2014

Workshop on Efficient Methods for Value of Information

Nicky Welton has invited me to talk at a very interesting workshop, which she has organised at the University of Bristol (here's a flyer). The day will be about the recent (and current) development of methods to perform calculations of the expected value of information, particularly for specific parameters (EVPPI).

This is something that is extremely relevant in health economic evaluation and I've already implemented a couple of possible methods in BCEA (in fact, we're writing more on this in the BCEA book $-$ we're running a little late on the original timeline, but it's looking good and I'll post more on this, later).

At the workshop, Chris Jackson and I will give a joint talk to describe how the different methods can be integrated in a single, general framework. We'll also have a new PhD student who will start working in September on fully Bayesian extension of Gaussian Processes approximations to the net benefit. Pretty exciting stuff (if you're easily excited by these kind of things, that is...).

Thursday, 14 August 2014

(Some) Spaces available

Requests for registration to our short course on Bayesian methods in Health Economics are coming in steadily $-$ in fact, we had started advertising quite in advance (the course is in November), but we're nearly booked up.

We set a total of 30 participants, so hurry up if you're interested! 

Monday, 11 August 2014

Two weights and two measures?

This is an interesting story about the Meningitis B vaccine (some additional background here and here). In a nutshell, the main issue is that vaccines are subject to a slightly different regulation than other "normal" drugs. For example, patents do not really apply to vaccines (I believe the argument is that the composition is so difficult to set up that in effect there is no point in patenting it $-$ although there may be more to this...).

More to the point, unlike "normal" drugs or health interventions, the economic evaluation of vaccines in the UK is within the remit of a special body, the Joint Committee on Vaccination and Immunisation (JCVI), rather than NICE

On the one hand, this is perfectly reasonable, as, arguably, vaccines do have some specific characteristics that make modelling and evaluation slightly more complex $-$ for example, vaccination is usually associated with phenomena such as herd immunity (the more people are vaccinated, the more people are directly or indirectly protected). While it is essential to include these dynamic aspects in modelling, it also makes for more complicated mathematical/statistical structures.

On the other hand, however, this raises the question as to whether it makes sense at all to try and evaluate these very special interventions using the same yardstick used for the others (eg cost-utility/effectiveness analysis). Or whether the thresholds for cost-effectiveness should be the same $-$ after all, infectious diseases may have incredible burden during epidemics and so, arguably, effective interventions may be worth extra money than the usual £20-30,000 per QALY.

There are all sort of related issues (some of which perhaps more of a political nature, for example in terms of the overall evaluation process, in direct comparison to what NICE do) $-$ I think I'll discuss them some more at a later stage. But this is interesting nonetheless, also from a technical point of view. 

In my opinion, the point is that, all the more for infectious diseases, to continuously re-assess the evidence and its implications for modelling is absolutely fundamental. Techniques such as the value of information (some discussed and available in BCEA) should be used more widely. And both regulators and industry should be open to this sort of step-wise approach to marketing.