Introduction to the New Statistics

Understanding The New Statistics 2012

   old_coverCumming, G. (2012). Understanding The New Statistics: Effect Sizes, Confidence Intervals, and Meta-Analysis. New York: Routledge

  • Explains estimation, with many examples.
  • Designed for any discipline that uses statistical significance testing.
  • For advanced undergraduate and graduate students, and researchers.
  • Comes with free ESCI software.
  • May be the first evidence-based statistics textbook.
  • Assumes only prior completion of any intro statistics course.
  • See the dance of the confidence intervals, and many other intriguing things.

The main message of the book is summarised in two short magazine articles, in The Conversation and InPsych, and on ABC Radio, and you can also download the book’s Preface, Contents, and a sample chapter. There is further information about the book available from the publisher and a new-statistics-users-guide explaining how to get the best out of the book.

The top journal Psychological Science now “embraces the new statistics.” See the new policy. It published my invited tutorial article to help authors adopt the new statistics where possible. Here is a brief summary of the advantages of making the change.

The author

gdcummingMy main current research is in the area of statistical cognition, which is the study of how people understand – or misunderstand – statistical concepts, and various different ways to present the results of statistical analyses.  I advocate the evidence-based practice of statistics, meaning that our selection of a statistical technique should be supported by cognitive evidence that people understand it well.

I am especially interested in replication, which is the topic of Chapter 5 in the book.  One of many reasons that CIs are better than p values is that CIs generally give quite good information about what is likely to happen on replication of an experiment, whereas a p value gives almost no information about replication.  The dance of the p values illustrates how p values vary enormously with replication, thus indicating how terribly uninformative they are.

You can contact me at E:


See the reviews on Amazon.

In this book Cumming does exactly what’s needed – he clearly explains significance-testing and confidence-interval techniques, and in the process leaves no doubt as to which should be preferred. I hope that this book will be read by anyone who plans to do research of any kind. Geoffrey Loftus, University of Washington, Seattle, USA

It is about time that the ‘new statistics’ get the place they deserve in statistics education, to further true understanding instead of following statistical rituals. Geoff Cumming’s excellent book is a milestone towards reaching that goal. Peter Sedlmeier, Chemnitz University of Technology, Germany

Geoff Cumming is a preeminent author in statistics reform and his new book is an important work in this area. Written in a clear, accessible way, Cumming covers essential topics in data analysis, including effect size estimation, confidence intervals, and meta-analysis. Readers in the social and behavioral sciences will learn new ways to look at their own results and avoid common traps of traditional significance testing. Rex Kline, Concordia University, Canada

Cumming makes strong arguments for confidence intervals and meta-analysis as better ways of representing and thinking about research. His graphical, interactive approach makes the ‘new statistics’ highly accessible and remarkably impactful on our statistical understanding. Robin K. Henson, University of North Texas, USA

See also a review by Eoin O’Connell in Significance: Statistics Making Sense

The software


View the original dance of the p values, as discussed in Chapter 5.

There are now 10 additional videos that present basic aspects of the new statistics. The list below gives the YouTube links. (Alternatively, go to YouTube and search for ‘Geoff Cumming.’) No. 9 in the list below is a new version of the dance of the p values.

The same 10 videos are also available via iTunes U.

One error

About 2.5 years after publication the first error found in the text was reported: In Equations 4.1 and 4.2 on p. 94, the left parenthesis should come just after the big sigma, not before it. My apologies!