A few drinks and a bit of big noting? The seamy and unattractive side of politics got an airing in this series of tweets by the resident professor of News Limited and SkyNews Peter Van Onselen:

Not the kind of story likely to last until Sunday, and so it proved. It’s largely behind The Australian’s paywall, but the extract gives the flavour:

The problem with models. So much of the decision making in government these days is made on the basis of what some statistics based model forecasts that there is cause for alarm over the case of the  oft-cited three-year-old finding that economic growth plummets when a country’s debt-to-GDP ratio exceeds 90%.

A Harvard Business Review blog summarises the controversy around Harvard economists Carmen Reinhart and Kenneth Rogoff in this way:

“Three University of Massachusetts economists — Thomas Herndon, Michael Ash, and Robert Pollin — came out with a working paper that recrunched the Reinhart and Rogoff data set and arrived at a very different result: instead of average -0.1% growth in countries with debt/GDP of more than 90%, they came up with 2.2% growth.

“Most of the attention since then has focused on an Excel error that Herndon, Ash, and Pollin found — which caused five countries to be excluded from the analysis — and Reinhart and Rogoff have subsequently acknowledged. That’s pretty embarrassing, but it only changed the result by 0.3 percentage points. Most of the difference had to do instead with how Reinhart and Rogoff weighted the results from different countries. They chose to give each country’s average growth in a particular debt/GDP range the same weight, regardless of how many years the country had been in that situation. As Herndon-Ash-Pollin write, this isn’t an indefensible approach (they do argue that Reinhart and Rogoff should have devoted a lot more ink to defending it). But by taking a different approach, and instead weighting countries’ results by how many years they were above 90% debt/GDP, they were able to get a very different result.

“This is watching the sausage of macroeconomics being made. It’s not appetizing. Seemingly small choices in how to handle the data deliver dramatically different results. And it’s not hard to see why: The Reinhart-Rogoff data set, according to Herndon-Ash-Pollin’s analysis, contained just 110 “country-years” of debt/GDP over 90%, and 63 of those come from just three countries: Belgium, Greece, and the UK.

“This is a problem inherent to macroeconomics. It’s not like an experiment that one can run multiple times, or observations that can be compared across millions of individuals or even hundreds of corporations. In the words attributed to economist Paul Samuelson, ‘We have but one sample of history.’ And it’s just not a very big sample.”

Healing our city. It was emotionally moving music for mourning; cellist Yo Yo Ma playing Bach’s Cello Suite No. 5 in C Minor as part of the memorial service in Boston for those who were gravely wounded or killed in the Boston Marathon bombing.

Yo-Yo Ma, who lives in Cambridge, Massachusetts, across the river from Boston, told NPR’s All Things Considered that he thinks of this piece as “a struggle for hope.” You can listen to it here.

The coolest kangaroo. National Geographic has a photo contest on its website. Will our national emblem be a winner? There are those who would say our entrant sums up the Australian character.

News and views noted along the way.