In many realms of science today, “statistical wisdom” seems to be in short supply. Misuse of statistics in scientific research has contributed substantially to the widespread “reproducibility crisis” afflicting many fields (SN: 4/2/16, p. 8; SN: 1/24/15, p. 20). Recently the American Statistical Association produced a list of principles warning against multiple misbeliefs about drawing conclusions from statistical tests. Statistician Stephen Stigler has now issued a reminder that there is some wisdom in the science of statistics. He identifes seven “pillars” that collectively provide a foundation for understanding the scope and depth of statistical reasoning.
Stigler’s pillars include methods for measuring or representing aggregation (measures, such as averages, that represent a collection of data); information (quantifying it and assessing how it changes); likelihood (coping with probabilities); intercomparison (involving measures of variation within datasets); regression (analyzing data to draw inferences); design (of experiments, emphasizing randomization); and residual (identifying the unexplained “leftovers” and comparing scientific models).

His approach is to identify the historical origins of these seven key pillars, providing some idea of what they are and how they can assist in making sense of numerical data. His explanations are engaging but not thorough (it’s not a textbook), and while mostly accessible, his writing often assumes a nontrivial level of mathematical knowledge. You’ll have to cope with expressions such as L(Θ)=L(Θ)|Χ and Cov(L,W)=E{Cov(L,W|S)}+Cov(E{L|S}, E{W|S}) every now and then.

While Stigler defends statistics from some of the criticisms against it — noting, for instance, that specific misuses should not be grounds for condemning the generic enterprise — he acknowledges that some issues are still a source of concern, especially in the new era of “big data” (SN: 2/7/15, p. 22). Using common statistical tests when many comparisons are made at once, or applying tests at multiple stages of an experimental process, introduces problems that the seven pillars do not accommodate. Stigler notes that there is room, therefore, for an eighth pillar. “The pillar may well exist,” he writes, “but no overall structure has yet attracted the general assent needed for recognition.”

Overuse of antibiotics in livestock can spread drug-resistant microbes — via farm workers or even breezy weather. But there’s more than one reason stay upwind of drugged cattle.

Dung beetles (Aphodius fossor) make their living on cattle dung pats, which are rich in nutritious microbes. To investigate the effects of cattle antibiotics on this smaller scale, Tobin Hammer of the University of Colorado at Boulder and his colleagues studied the tiny communities around tetracycline-dosed and undosed cows. Compared with untreated cows’ dung, microbes in dung produced by treated cows were less diverse and dominated by a genus with documented resistance, the researchers report May 25 in the Proceedings of the Royal Society B.

Beetles typically reduce methane gas wafting off dung, but pats from treated cows showed a 1.8-fold increase in methane output. How this might figure into greater cattle methane production remains to be studied, but Hammer and company speculate that the antibiotics may wipe out the bacterial competition for microbial methane factories.

Editor’s note: On May 3, 2017, Science retracted the study described in this article. Based on findings from a review board at Uppsala University, Science cites three reasons for pulling the study: The experiments lacked ethical approval, the original data do not appear in the paper and questions emerged about experimental methods.

Microscopic pieces of plastic rule Earth’s oceans, with numbers in the billions — possibly trillions. These tiny plastic rafts provide homes to microbes (SN: 2/20/16, p. 20), but their ecological effects remain murky.
In a lab at Uppsala University in Sweden, researchers exposed European perch (Perca fluviatilis) larvae to a microplastic called polystyrene to see how they might react. The exposure triggered a slew of potentially negative effects: Fewer eggs hatched, growth rates dropped and feeding habits changed, with some larvae preferring polystyrene to more nutritious food options. Exposed larvae were also sluggish in responding to scents that signal approaching predators in the wild, the team reports in the June 3 Science.

European perch, a keystone species in the Baltic Sea, have recently experienced a population dive. Because the drop has been linked to juvenile feeding issues, the researchers argue that microplastics could be to blame.