Sunday, 1 March 2015

Non-trivial wedges

During February, I've been really bad at blogging $-$ I've only posted one entry advertising our workshop at the RSS, later this month. I have spent a lot of time working in collaboration with colleagues at UCL and the London School of Hygiene and Tropical Medicine to prepare a special issue of the journal Trials.

We've prepared 6 articles on the Stepped Wedge (SW) design. This is a relatively new design for clinical trials $-$ it's basically a variant of cluster RCTs, in which all clusters start the study in the control arm and then sequentially switch to the intervention arm, in a random order, until all the clusters are given the intervention. 

There are some obvious limitations to this design (first and foremost the fact that there may be a time effect over and above the intervention effect, which means that time needs to be controlled for, to avoid bias). But, as we show in our several articles, there may be some benefits in applying it $-$ I think we've been very careful in detailing them, as practitioners need to be fully aware of the drawbacks.

The paper I've been working on mostly is about sample size calculations for a SW trial. Some authors have presented analytical formulae to do these, but while they work in specific circumstances, there are several instances in which the features of the SW formulation (time effect, repeated measurements on the same individuals in the clusters, etc) are better handled through a simulation-based approach, which is what we describe in details in our paper. 

I'm also finalising a R package in which I'll collect the functions I've prepared to sort-of-automate the calculations, for a set of relatively general situations. I'm planning on naming the package SWSamp (Samp have won today, so I'm all up for it, right now $-$ we'll see how they when I get closer to finishing it, though...).

Sunday, 1 February 2015

GAS workshop

The General Application Section (GAS) of the Royal Statistical Society has asked us to reenact the session Richard Nixon, Chris Jackson and I did at Bayes Pharma last year on Bayesian methods in health economic evaluationIn fact, we have a nice addition, as we asked Nicky Welton to contribute a talk on multi-parameter evidence synthesis 

I think it'll be an interesting event. The meeting/workshop will be held at the RSS HQ in London on Friday 27th March 2015, from 2pm to 5.15pm (there's a registration fee, I'm afraid and I think it'll be on a first-come, first-served base).

Friday, 30 January 2015

More than Word

I know this will sound childish and possibly snobbish. But for some reason (mostly because of several collaborative papers I'm working on at the moment with colleagues that do not use LaTeX), I have spent a good 90% of my working time on MS Word, in the last week or so. 

I have abjured Windows a long time ago and frankly even for maths-free writing, I still think that LaTeX is the best option; but in honesty, I also think that Libre/OpenOffice are not just as good as their corresponding MS Office alternatives. 

Most of the time, WINE is more than enough for my Windows sins $-$ and it has been of late. But I'm really looking forward to finishing these few Word-bound things and go back to Word-free docs!

Tuesday, 20 January 2015

A bunch of papers

The beginning of the new year has been particularly busy, as I'm working on several interesting projects. On the bright side, some of these are starting to give their fruits and, coincidentally, in the last few days we've had a few papers finalised (ie published, accepted for publication or submitted to the arxiv in an advanced status).

The first one has been published in Cost Effectiveness and Resource Allocation (the open access version is here). I've been involved in this paper with colleagues at UCL. The paper is an economic evaluation of an interesting and rather complex community trial conducted in Malawi, a country with particularly low life expectancy and high rates of HIV. In the paper, we did most of the economic analysis using BCEA.

The second one has also just been published in Pharmacoeconomics and is an "educational" piece that I co-wrote with several colleagues at UCL. I think this too was an interesting piece of work, in that we tried to focus on several statistical issues that are of concern in many economic evaluations $-$ the idea that health economics is in many ways inextricably related to statistics is of course one of my pieces de resistance (I guess I've showed off enough complicated words for a post...).

The third one is the RDD paper, which we had submitted ages ago to Statistics in Medicine. I had a brilliant experience with the Structural Zeros paper $-$ I submitted the first version in August and the paper was online by November. This time around, we had to struggle a lot more (apparently they couldn't find suitable reviewers, then the reviews arrived but took some time, then we responded to the comments $-$ long story short, it's been almost one year). Anyway, finally, they seem to have accepted the paper (which we previously arxived a similar version); we need a couple more changes and we should be good to go (I hope I'm not jinxing it!).

Finally, the last one is part of one of my PhD students (technically, I'm only second-supervising him). In fact, the paper develops a nice Bayesian non-parametric model to perform clustering and model selection simultaneously. We developed the model to handle a real clinical dataset, which records data on patients with lower urinary tract infection. I only knew little about Bayesian NP before working on this, so it was a nice opportunity. William has done a very good job in sorting this out and we have also submitted the full paper to Statistics in Medicine (hopefully, we'll get a quick turnaround!).

Monday, 19 January 2015

DIA Joint Adaptive Design and Bayesian Statistics Conference

This is my first real contribution to the ISBA Section on Biostatistics and Pharmaceutical Statistics, in my new role of secretary. Our section has formally endorsed this very interesting conference $-$ the timeline is very short, as the conference will start on February 11th.

The conference has two very interesting tutorials (the first one on Bayesian Methods for Drug Safety Evaluation and Signal Detection, given by David Olhsen and Amy Xia; and the second one on Use of Historical Data in Clinical Trials, taught by Heinz Schmidli). There'll also be other interesting talks and discussion.

In the Biostats/Pharma section, we'll try to organise (either directly, or through endorsement, or some other form) a few similar meetings (Bayes Pharma is of course another interesting one). 

Monday, 12 January 2015

No-go zones?

I think this is really serious: that's the story of an "expert" on terrorism, who's commented on Fox News about the situation in Europe. If you really want to laugh about it, you just take this at face value, as, erm, let's just say, "somebody" who just said a bunch of nonsense on TV.

But I think there's so much more to it, particularly after hearing an interview with this guy (on the BBC Radio 4 programme PM $-$ I'm sure there'll be a link to today's broadcast shortly). The point is that this guy is kind of defending himself by just saying that he's sorry for not having done his homework properly, and just taking as true oral information coming from some sources. He said he had used these sources in the past, so effectively didn't even bother to stop and think whether he was making a fool of himself.

It's astounding that you can get away, on TV, by just making a claim such as "in London, Muslim religious police beat anyone who doesn't dress according to Muslim, religious Muslim attire" (which is just not true!) without pointing out to any hard evidence to substantiate your claim. 


In fact, I think there's a wider problem: when I was reading the book on Enron scandal, I had noticed that quite often the authors stated something like "a source says...", or "one of the people involved in this said...", without going in to the details (NB: I should say that this is not an attack to the authors of that book $-$ just the way it is, I guess). Of course, in our line of work, you could never do anything like that. I suppose it may be time the media start following suit...

Monday, 5 January 2015

Sabbath-ical

Today is the first day of my sabbatical term, which I have asked (and obtained) so I could work on writing the books $-$ the BCEA book had been commissioned for a while and it's not far from a nearly finalised version, while the 2nd edition of Bayesian Approaches to Clinical Trials and Health Care Evaluation (which I am co-authoring with relatively minor and unknown researchers, as some may say...) is slightly behind.

Although it wasn't a formal sabbatical, on another occasion I spent a relatively large chunk of time working from home $-$ that's back when I was working in Siena and was also collaborating to the write up of another book. Back then, it was a strange experience $-$ after a while, I wasn't really enjoying very much not going to the office every day and was actually, actively missing it. Part of it is probably that the office was bang in the middle of Siena (and this was the view)...

This time it will be probably quite different, as I will still go to the office once/twice a week (mostly for meetings and stuff), but at least I got to dump (in the friendliest way possible, I hope!) most of my teaching to Aidan, who's been so kind to cover for me, this term. Anyway, I keep telling people that, because I'm on sabbatical, this term will be good as I'll be able to do lots of work $-$ I just hope I've not already overbooked (pun intended!) myself...

Sunday, 4 January 2015

Advance notice

As a few people have already inquired (more or less formally) about the next edition of the short course on Bayesian Methods in Health Economics, I thought it would be nice to start the new year off by posting some details on that...

While we're exploring avenues for world domination and as yet unjustified expansion that will possibly, eventually lead us to be the Enron of statistical education (I'll post about this when I have a less confused idea about it), we know that the next edition will be held at the MRC Biostatistics Unit in Cambridge on 24-26 November, later this year (that's Tuesday to Thursday).

I think we'll very much keep the same format, which I think has worked fairly well in the two previous editions $-$ with only very minor tweaks, particularly to the first and, possibly last two talks. We may revise some of the practicals, but again I think that they kind-of work well, so I'm not sure about that... We'll re-advertise more widely closer to the event, but you can put the dates in your diary (and yes: we did have to book the room so much in advance!).