I’ve got several imminent deadlines which means that my blog time is limited just now. However, there have been a few interesting posts that I thought I’d refer you to.
Orac has a review of a new study showing that publication bias can result in some animal research studies.
So, basically, all we can conclude from this study is that, for one intervention and one type of animal model, there appears to be publication bias, the effect of which can only be very roughly estimated and which varies depending upon which intervention is studied. It is unknown whether publication bias exists for other animal models and, if so, how much, but it would be shocking indeed if it did not exist for at least some animal models of disease and treatment.
DrugMonkey discusses how an erroneous desire to reduce the confidence level of a study below 0.05 can push some researchers to include more animals in their research than is necessary.
So imagine yourself on an Institutional Animal Care and Use Committee. One of the things you are supposed to evaluate is if the number of rats proposed to study, say, mephedrone is excessive. Roughly speaking let us stipulate that N=6 gives us the minimum power required to get a significant p-value; N=12 is robust. A decent chance of p < 0.01. But the PI is asking for N=18 per group so that the error bars look super tight and that notorious Reviewer #3 won't complain that the p < 0.05 doesn't seem real to him.
What group size are you going to approve? On what basis? How do you reconcile Reduction with the eyeball inference technique?
[I]t’s incredible to me that so many people who fancy themselves liberals and progressives, who otherwise spend so much of their time objecting to the government using its authority to squash minority viewpoints and undermine our freedom, suddenly want to give government even more authority to police not our actions but our beliefs and our words.
Finally, Laelaps has his review of a new study that finds greater diversity in mouse lemurs than was previously thought:
While the authors do note that their hypothesis is provisional, the end result of their analysis recovered as many as 16 genetically distinct mouse lemur populations, some of which fit in with known species while others may represent diverging lineages. The question is whether each of the cryptic lineages represents a new species. The authors argue that, since new species become distinguished when they begin to genetically diverge from their parent stock, each of the 16 genetic lineages could be recognized as a distinct species, though other researchers might prefer different criteria based upon reproductive isolation, physical characteristics, or other indicators that show up later after divergence.