Category: NHST

Adventures in Replication – Reviewers don’t want to believe disappointing replication results

Trying to publish replication results is difficult.  Even when the original evidence is very weak or uncertain, reviewers tend to look for reasons to explain away a smaller effect in the replication.  If nothing comes to mind, reviewers may even

Posted in NHST, Replication, The New Statistics

Beyond p values – Dispatches from the ASA symposium on statistical inference

The next couple of posts will be about my experience at the ASA conference on statistical inference: A World Beyond p < .05. The first session featured Steve Goodman and John Ioannidis (who Skyped in from Australia).  One highlight was

Posted in NHST, Teaching, The New Statistics

Adventures in Replication: p values and Illusions of Incompatibility

Here’s an idea I run into a lot in peer reviews of replication studies: If the original study found p < .05 but the replication found p > .05, then the results are incompatible and additional research is needed to

Posted in ITNS, NHST, Replication, Statistical graphics, The New Statistics

p values and outrageous results

If you were researching a muscle-building supplement and read that a test of the supplement produced an increase in muscle mass by 200% within a month, you’d be right to be skeptical.  Perhaps randomization had broken down, perhaps there was

Posted in NHST

Danny Kahneman: From p values to Nobel Prize

You meet a red-headed person who is a bit short-tempered then, later, another who is similarly touchy. You start to believe that red hair signals ‘watch out’. Really? You are leaping to a conclusion from an extremely small sample! But

Posted in ITNS, NHST, Replication

From NHST to the New Statistics — How do we get there?

APS just wrapped up.  Geoff and I were privileges to help host a symposium on making progress moving the field away from p values towards the New Statistics.  Our co-conspirators were fellow text-book author Susan Nolan, Psychological Science editor Stephen

Posted in NHST, Open Science, Teaching, The New Statistics

The persistence of NHST: “Wilfully stupid”?

I recently gave a research talk to Psychology at La Trobe, my old University–although I now live an hour out of the city and rarely visit the campus. I decided to turn things around from my previous few talks: Instead

Posted in NHST, Replication, The New Statistics

p intervals: Replicate and p is likely to be *very* different!

The Significance Roulette videos (here and here) are based on the probability distribution of the p value, in various situations. There’s more to the second video than I mentioned in my recent post about it. The video pictures the distribution of replication

Posted in NHST, Replication

Significance Roulette 2

In my post of a couple of days ago I gave the link to Significance Roulette 1, a video that explains how to generate the roulette wheel for a ‘typical experiment’, by which I meant an independent groups experiment, N = 32

Posted in ITNS, NHST, Replication, The New Statistics

Significance Roulette 1

If you run an experiment, obtain p = .05, then repeat the experiment–exactly the same but with a new sample–what p value are you likely to get? The answer, surprisingly, is just about any value! In other words, the sampling

Posted in ITNS, NHST, Replication, The New Statistics