Archive for February, 2012

Radical Statistics was radical

25th February, 2012 Leave a comment

Today I went to the Radical Statistics conference in London. RadStats was originally a sort of left wing revolutionary group for statisticians, but these days the emphasis is on exposing dubious statistics by companies and politicians.

Here’s a quick rundown of the day.

First up Roy Carr-Hill spoke about the problems with trying to collect demographic data and estimating soft measures of societal progress like wellbeing. (Household surveys exclude people not in households, like the homeless soldiers and old people in care homes; and English people claim to be 70% satisfied regardless of the question.)

Next was Val Saunders who started with a useful debunking of done methodological flaws in schizophrenia research, then blew it by detailing her own methodologically flaws research and making overly strong claims to have found the cause of that disease.

Aubrey Blunsohn and David Healy both talked about ways that the pharmaceutical industry fudges results. The list was impressively long, leading me to suspect that far to many people have spent far too long thinking of ways to game the system. The two main recommendations that resonated with me were to extend the trials register to phase 1 trials to avoid unfavourable studies being buried and for raw data to be made available for transparent analysis. Pipe dreams.

After lunch Prem Sikka pointed out that tax avoidance isn’t just shady companies trying to scam the system, but actually accountancy firms pay people to dream up new wheezes and sell them to those companies.

Ann Pettifor and final speaker Howard Reed had similar talks evangelising Keynesian stimulus (roughly, big government spending in times of recession) for the UK economy amongst some economic myth debunking. Thought provoking, though both speakers neglected to mention the limitations of such stimuli – you have to avoid spending in pork barrel nonsense (see Japan in the 90s, that buy-a-banger scheme in the UK in 2009) and you have to find a ways to turn of the taps w when recession is over.

The other speaker was Allyson Pollack who discussed debunking a dubious study by Zac Cooper claiming that patients being allowed to choose their surgeon improved success rated treating acute myocardial infarction. Such patients are generally unconscious while having their heart attack so out was inevitably nonsense.

Overall a great day.

GUI building in R: gWidgets vs Deducer

20th February, 2012 5 comments

I’ve been a user (and fan) of gWidgets for a couple of years now for GUI building in R. (See my introduction to it here.) However, it’s always good to check out the competition so I’ve been playing around with Deducer to see how they compare.

R can access a number of GUI building frameworks including tcltk, GTK, qt, and Java, not to mention HTML. gWidgets’ big selling point is that is provides a high-level wrapper to all the R wrappers for each framework, so you can write code in a toolkit independent way. Switching between tcltk and GTK and qt won’t often be that useful, but if you think you might want to move from a desktop based GUI to a web app, it makes the transition easier. By contrast, Deducer based upon the rJava, and provides access to the Java Swing framework. It’s a slightly lower level library (which means you have to write more lines of code to achieve the same thing), but since you get full access to Swing, it’s a little more flexible. Deducer also has some features to integrate your GUIs with JGR, so if you use that for running R, it’s perhaps the most natural choice.

To test the two frameworks, I wrote a small GUI for running the Kolmogorov-Smirnoff test (that one of the ones for checking whether or not a variable seems to have been sampled from a particular distribution). Take a look at the code below to see the comparison. (Regular reader may notice I’ve switched from my usual under_casing to camelCasing. Both the frameworks use this style, so I thought I’d follow suit for cleanliness.)

First, here are some common variables (labels and the like).

#Some sample data to test against
x1 <- rnorm(100)
x2 <- runif(100)

#Widget labels
labelX <- "Variable name for data: "
labelY <- "Distribution to compare to: "
labelAlternative <- "One or two sided test?: "
labelP <- "The p-value is: "

#Choices for comboboxes
choicesAlternative <- eval(formals(ks.test)$alternative)
distributions <- c(
    normal = pnorm, 
    exponential = pexp,
    F = pf,
    "log-normal" = plnorm,
    "Student's t" = pt,
    uniform = punif

This is the gWidgets GUI

createKsTestGwidgets <- function()
  options(guiToolkit = "tcltk")
  win <- gwindow("KS Test, gWidgets edition", visible = FALSE)
  frmX <- gframe("x", container = win)
  lblX <- glabel(labelX, container = frmX)
  txtX <- gedit(container = frmX)
  frmY <- gframe("y", container = win)
  lblY <- glabel(labelY, container = frmY)
  cmbY <- gcombobox(names(distributions), container = frmY)
  frmAlternative <- gframe("alternative", container = win)
  lblAlternative <- glabel(labelAlternative, container = frmAlternative)
  cmbAlternative <- gcombobox(choicesAlternative, container = frmAlternative)
  btnCalc <- gbutton("Calculate", container = win,
      handler = function(h, ...)
        x <- get(svalue(txtX), mode = "numeric")
        y <- distributions[[svalue(cmbY)]]
        alternative <- svalue(cmbAlternative)
        ans <- ks.test(x, y, alternative = alternative)
        svalue(txtP) <- format(ans$p.value, digits = 3)
  frmResults <- gframe("results", container = win)
  lblP <- glabel(labelP, container = frmResults)
  txtP <- gedit(container = frmResults)
  visible(win) <- TRUE


…and here’s the Deducer equivalent.

createKsTestDeducer <- function()
  win <- new(RDialog)
  win$setSize(300L, 500L)
  win$setTitle("KS TEST, Deducer edition")
  JLabel <- J("javax.swing.JLabel")
  lblX <- new(JLabel, labelX)
  addComponent(win, lblX, 1, 1000, 50, 1, rightType = "REL")
  txtX <- new(TextAreaWidget, "x")
  addComponent(win, txtX, 51, 1000, 150, 1, rightType = "REL")
  lblY <- new(JLabel, labelY)
  addComponent(win, lblY, 151, 1000, 200, 1, rightType = "REL")
  cmbY <- new(ComboBoxWidget, names(distributions))
  addComponent(win, cmbY, 201, 1000, 300, 1, rightType = "REL")
  lblAlternative <- new(JLabel, labelAlternative)
  addComponent(win, lblAlternative, 301, 1000, 400, 1, rightType = "REL")
  cmbAlternative <- new(ComboBoxWidget, choicesAlternative)
  addComponent(win, cmbAlternative, 401, 1000, 500, 1, rightType = "REL")
  JButton <- J("javax.swing.JButton")
  btnCalc <- new(JButton, "Calculate")
  addComponent(win, btnCalc, 501, 1000, 601, 1, rightType = "REL")
  ActionListener <- J("org.rosuda.deducer.widgets.event.RActionListener")
  listener <- new(ActionListener)
  calculationHandler <- function(cmd, ActionEvent)
    x <- get(txtX$getText())
    y <- distributions[[cmbY$getModel()]]
    alternative <- cmbAlternative$getModel()
    ans <- ks.test(x, y, alternative = alternative)
    txtP$setText(format(ans$p.value, digits = 3))
  lblP <- new(JLabel, labelP)
  addComponent(win, lblP, 601, 1000, 650, 1, rightType = "REL")
  txtP <- new(TextAreaWidget, "results")
  addComponent(win, txtP, 651, 1000, 750, 1, rightType = "REL")


Note that the Deducer example works perfectly under JGR, though I couldn’t get the button handler to fire when running it from eclipse. This is likely due to my inexperience with the toolkit rather than a fundamental problem with the framework. Many of the lines are more or less a one-to-one comparison, but Deducer requires you to explicitly specify positions of widgets, and is a little more verbose when you come to add event handling logic.

Either or these frameworks is suitable for the obvious use case of GUI building in R (rapid prototyping of front-ends for non technical users, and for teaching demos), so don’t sweat your decision too much.

Edit: Fixed variable name casing issues.

R hits 10000 questions on stackoverflow

17th February, 2012 Leave a comment

R's 10000th question on stackoverflow

A milestone, though not that exciting as questions go. Still, if you haven’t yet joined the cult of Stack Exchange, take a look here.

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