Advances in Psychometric Theory and Measurement for Psychological Sciences

With Tutorials in R

This is an educational resource, with content at the cutting edge of scientific knowledge. It aims to improve future research, by improving researchers knowledge in the statistical inferences made, planning better experiments and analyzing scientific research being carried out with more rigor and transparency.

Overview

Academic discourse and its grammar not only are like a forest that doesn’t allow us to distinguish between individual trees but also go a step further, forcing the researcher to cut the trees down in order to understand the forest. Paul B. Preciado, Countersexual Manifesto

Psychometrics is an area that is growing rapidly worldwide: while many still measure psychological phenomena without having evidence that the measurement has some quality or validity evidence, others continue on the more difficult, but much more precise and scientific, path. The book Advances in Psychometric Theory and Measurement for Psychological Sciences: With Tutorials in R is the first book that makes psychometric science and measurement theory more accessible to you, the reader. Covering classical and modern views on psychometrics, I introduce concepts crucial to understanding psychometrics. This book is aimed at students and teachers who wish to use and understand psychometrics in depth. It’s a great resource for studying alone or for study groups.

In this book I teach the theory behind the concept of the analysis, but I also teach how to run the analysis in R programming language. We use R because it is free, accessible, and easy to use.

This book is intended to be an educational resource for everyone. The content is written in an accessible way and it is possible to deduce conclusions, without being shallow.

This book integrates information from my scientific work, in addition to several other works that are at the cutting edge of knowledge. The purpose of this book being online is to make the information more accessible and easier to update in the future.

Suggest Edits and Improvements

If you find any mistakes or have suggestions for improvement, you can send an email regarding this open educational resource. You can also download a PDF or epub version (click the download button in the menu on the top left). This work is shared under a CC-BY-NC-SA License.

Support my work

Please help keep this book maintained and free for everyone by supporting me through my Ko-fi page.

APA Citation

You can cite this book as:

Degobi, E. B. (2025). Advances in Psychometric Theory and Measurement for Psychological Sciences: With Tutorials in R.

BibTeX

@book{Degobi2025,
  title     = "Advances in Psychometric Theory and Measurement 
  for Psychological Sciences: With Tutorials in R",
  author    = "Degobi, Ellie B.",
  publisher = {https://elliedegb.quarto.pub/psychometrics/},
  year      = 2025,
  doi       = ,
  url       = {https://elliedegb.quarto.pub/psychometrics/}
}

About the Author

The current maintainer of the book is Ellie Bastos Degobi, the creator of this educational resource. I’m a Ph.D. and M.Sc. in Psychology, specializing in Psychological Assessment from São Francisco University (Campinas - Brazil). Additionally, I have a Bachelor’s in Psychology from the Pontifical Catholic University of Rio de Janeiro (PUC-RIO). My expertise spans across various domains within psychology, with a primary focus on the following areas:

• Psychometrics/Measurement
• Mental Health
• Meta-Science
• Quantitative Methods
• Construction of Instruments

Photo of the author Ellie Bastos Degobi

I dedicate this work to Phoebe, my lifelong love and partner.