flynn002

Yesterday I had the pleasure of hearing George Davey Smith (aka @mendel_random) talk. In the course of a wide-ranging lecture he recounted his experiences with conducting a systematic review. This caught my interest, as I’d recently considered the question of literature reviews when writing about fallibility in science . George’s talk confirmed my concerns that cherry-picking of evidence can be a massive problem for many fields of science. Together with Mark Petticrew, George had reviewed the evidence on the impact of stress and social hierarchies on coronary artery disease in non-human primates. They found 14 studies on the topic, and revealed a striking mismatch between how the literature was cited and what it actually showed. Studies in this area are of interest to those attempting to explain the well-known socioeconomic gradient in health. It’s hard to unpack this in humans, because there are so many correlated characteristics that could potentially explain the association. The pr...

At a recent conference, someone posed a question that had been intriguing me for a while: suppose you have limited resources, with the potential to test N participants. Would it be better to do two studies, each with N/2 participants, or one big study with all N? I've been on the periphery of conversations about this topic, but never really delved into it, so I gave a rather lame answer. I remembered hearing that statisticians would recommend the one big study option, but my intuition was that I'd trust a result that replicated more than one which was a one-off, even if the latter was from a bigger sample. Well, I've done the simulations and it's clear that my intuition is badly flawed. Here's what I did. I adapted a script that is described in my recent slides that give hands-on instructions for beginners on how to simulate data, The script, Simulation_2_vs_1_study_b.R , which can be found here, generates data for a simple two-group comparison using a t-test. In...

 Doing research, analysing the results, and writing it up is a prolonged and difficult process. Submitting the paper to a journal is an anxious moment. Of course, you hope the editor and reviewers will love it and thank you for giving them the opportunity to read your compelling research. And of course, that never happens. More often you get comments from reviewers pointing out the various inadequacies of your grasp of the literature, your experimental design and your reasoning, leading to further angst as you consider how to reply. But worse than this is silence. You hear nothing. You enquire. You are told that the journal is still seeking reviewers. If you go through that loop a few times, you start to feel like the Jane Austen heroine who, having dressed up in her finery for the ball, spends the evening being ignored by all the men, while other, superficial and gaudy women are snapped up as dance partners. There have been some downcast tweets in my timeline about papers getting ...

Source: http://www.weblogcartoons.com/2008/11/23/ideas/ Those of you who follow this blog may have noticed a lack of thematic coherence. I write about whatever is exercising my mind at the time, which can range from technical aspects of statistics to the design of bathroom taps. I decided it might be helpful to introduce a bit of order into this chaotic melange, so here is a catalogue of posts by topic. Language impairment, dyslexia and related disorders The common childhood disorders that have been left out in the cold (1 Dec 2010) What's in a name? (18 Dec 2010) Neuroprognosis in dyslexia (22 Dec 2010) Where commercial and clinical interests collide: Auditory processing disorder (6 Mar 2011) Auditory processing disorder (30 Mar 2011) Special educational needs: will they be met by the Green paper proposals? (9 Apr 2011) Is poor parenting really to blame for children's school problems? (3 Jun 2011) Early intervention: what's not to like? (1 Sep 2011) Lies, damned li...

There's been debate over the new terminology for Developmental Language Disorder (DLD) at a meeting (SRCLD) in the USA. I've not got any of the nuance here, but I feel I should make a quick comment on one issue I was specifically asked about, viz: As background: the field of children's language disorders has been a terminological minefield. The term Specific Language Impairment (SLI) began to be used widely in the 1980s as a diagnosis for children who had problems acquiring language for no apparent reason. One criterion for the diagnosis was that the child's language problems should be out of line with other aspects of development, and hence 'specific', and this was interpreted as requiring normal range nonverbal IQ (nviq). The term SLI was never adopted by the two main diagnostic systems -WHO's International Classification of Diseases (ICD) or the American Psychiatric Association's Diagnostic and Statistical Manual (DSM), but the notion that IQ should ...

In Merchants of Doubt , Eric Conway and Naomi Oreskes describe how raising doubt can be used as an effective weapon against inconvenient science. On topics such as the effects of tobacco on health, climate change and causes of acid rain, it has been possible to delay or curb action to tackle problems by simply emphasising the lack of scientific consensus. This is always an option, because science is characterised by uncertainty, and indeed, we move forward by challenging one another’s findings: only a dead science would have no disagreements. But those raising concerns wield a two-edged sword: spurious and discredited criticisms can disrupt scientific progress, especially if the arguments are complex and technical: people will be left with a sense that they cannot trust the findings, even if they don’t fully understand the matters under debate. The parallels with Merchants of Doubt occurred to me as I re-read the critique by Gilbert et al of the classic paper by the Open Science Colla...