quotable: “I spend a lot of time on this task. I should write a program automating it!”
Quotable: “how long can work on making a routine task more efficient before you’re spending more time than you save?”
John Rauser on this oft-cited dictum of percentile usage in monitoring, and when it’s wrong and it’s actually possible to reason with averaged percentiles, and when it breaks down.
In their paper at PNAS, they write: “the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. These results question the validity of some 40,000 fMRI studies and may have a large impact on the interpretation of neuroimaging results.” For example, a bug that’s been sitting in a package called 3dClustSim for 15 years, fixed in May 2015, produced bad results (3dClustSim is part of the AFNI suite; the others are SPM and FSL). That’s not a gentle nudge that some results might be overstated: it’s more like making a bonfire of thousands of scientific papers. Further: “Our results suggest that the principal cause of the invalid cluster inferences is spatial autocorrelation functions that do not follow the assumed Gaussian shape”. The researchers used published fMRI results, and along the way they swipe the fMRI community for their “lamentable archiving and data-sharing practices” that prevent most of the discipline’s body of work being re-analysed. ®
‘a Ruby regular expression editor and tester’. Great for prototyping regexps with a little set of test data, providing a neat permalink for the results
Links for 2016-07-05
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