- The slides for most of the talks at the Shoucheng Zhang memorial workshop are now available - there are pdf links on the schedule page.
- Charles Kittel has passed away. I have not been able to find an obituary online anywhere yet - I will update this accordingly when one appears. (The closest I've been able to find is here.) He was a great physicist - he is one of the Ks in the RKKY interaction, and had a big impact on physics pedagogy through his books, which include: the mechanics volume of the Berkeley Physics Course; the grad level Quantum Theory of Solids; the undergrad level Introduction to Solid State Physics; and Thermal Physics with Herb Kroemer.
- Much more has been written in the last couple of days about Murray Gell-Mann passing away. See the NY Times, the Washington Post, and Science News, for example.
- Back in January, a study was published in Science Advances that makes a compelling case that the physics subject GRE is basically useless as a predictor of performance in grad school.
- The NSF has a video with their advice on how to review proposals.
- The National Academy has released its decadal survey, Frontiers of Materials Research. You can download a free pdf copy (at least, from within the US you can; not sure about non-US readers). Some controversy from one of the sponsors....
- As pointed out by a commenter on the previous post, there is an updated version of the paper from last year was a report of superconductivity in Ag-decorated Au nanoparticles dropcast as a film. An optimistic discussion is here. As I said at the time, extraordinary claims require extraordinary evidence - at least, independent verification.
A blog about condensed matter and nanoscale physics. Why should high energy and astro folks have all the fun?
Saturday, May 25, 2019
Brief items
A number of interesting items:
The GRE paper is not very good. First, their measure of grad school performance is completion, i.e. a binary variable. They are suppressing the range of the dependent variable, which is guaranteed to weaken correlations.
ReplyDeleteAlso, they include the ranking of the grad program as an independent variable, i.e. a variable that is strongly correlated with GRE scores. This collinearity means that estimated coefficients in their regression model will have huge uncertainties, making it harder to get any non- zero coefficients to be statistically significant.
This is all analyzed here:
https://arxiv.org/abs/1902.09442
Furthermore, I wrote something in response to another study, looking at how selection effects should reduce correlations in the data. Indeed, a perfectly efficient sitting process would remove predictive validity from all variables, even if we don't truncate the dependent variables:
https://arxiv.org/abs/1709.02895
In short, we should leave this sort of data analysis to statisticians and social scientists, who are much better at this than physicists.
Sponsors, plural? Naive question: how much do these decadal surveys cost?
ReplyDeleteAlex, thanks for the links. Precise statements about statistical significance aside, in a study of our own program we saw a very similar situation- grad gpa and degree completion seemed uncorrelated with subject gre. Of course, there are big selection effects at work here, as we were only looking at the students who had actually matriculated into our program. Similarly,the published study is only looking at students who did get admitted to some doctoral program.
ReplyDeleteAnon, my impression was that materials parts of the DOE cosponsored the study. I’m not sure about the costs - presumably there are travel costs associated with bringing the panel together for some small number of face to face meetings, for “townhalls” at APS and MRS, and some staff support at the NAS for the actual editing and document preparation. Still, all of that seems like small numbers. Perhaps a reader with more knowledge could comment here.
Doug, the total cost of the decadal study must be around $1M. The NSF portion was $458,000. See here: https://nsf.gov/awardsearch/showAward?AWD_ID=1647113
ReplyDeleteMaybe not surprising NSF complained when they did not get what they paid for.
Anon@3:13pm, thanks for the numbers; I should've thought of doing that. As for whether the NSF got "what they paid for", I need to read the whole study to have a more informed opinion. Generically, a charge is given to the study group and they go to work, often with the sponsors checking in occasionally to make sure that any ambiguities are resolved. The reason the comments are controversial is that it can come across like slagging the people who volunteered a bunch of time and effort to do the study.
ReplyDeleteAnd Ted Geballle turns 100 next year! I'm told he's still in everyday working for a few hours and just applied for beam time to do some work on a new class of cuprates.
ReplyDeletehttps://www.theguardian.com/education/2019/jun/05/insecure-employment-for-postdoc-researchers-is-leading-to-bad-science?fbclid=IwAR0kQtPOrW8W2H0Zw__AhyxQQsUyiSYOj01_V7a9Pa9rxzsr6selBPhLFGs
ReplyDeleteFYI, videos for most of the talks at the Shoucheng Zhang workshop are now available as well.
ReplyDelete