OM book glossary

This is the glossary for the book “Outcome measures and evaluation in counselling and psychotherapy” written by myself and Jo-anne Carlyle and available now from SAGE. I am over 430 entries now and still climbing though now (April 2026) I am concentrating more on harmonising, cleaning up and cross-linking existing entries than I am on adding new ones. Some glossary entries link to more detailed expansions of the topic in my Rblog and, at last, an increasing number now link with interactive online (“shiny”) apps.

You can see the alphabetical list of entries below which is a good place to browse, or you can use this search box.

Beware if you are searching, the way that the plugin orders the matches is to my mind bizarre so scroll down if what you typed isn’t first on the list, you may find something with exactly the word or phrase you typed in to find is hidden further down the list of suggestions. As of 29.ix.26 the plugin authors are aware and working on this.

As to the content, if a topic you want is not there and you think it should be, contact me and tell me and I will put it on the (long!) list of entries to be added!

T

t-scores

I probably last saw this in the last century but I'll put it in anyway! Details Essentially…

t-test = "Student's t-test"

Historically one of the paradigmatic, genuinely paradigm changing, statistical "tests". It tests how likely it…

Test-retest effect/artefact/artifact

I think we should really say "test-retest effect" and I often put scare quotes around…

Test-retest reliability

This is one of the fundamental ways of exploring the reliability of a measure. …

Tests of fit to a distribution

There are a number of situations in which we might want to test the fit…

The "third sector"

Term much used in the UK (and elsewhere?) to denote charities and charity funded work….

The 3 E's: Efficacy, Effectiveness & Efficiency

From the hugely influential monograph: Cochrane, A. L. (1972). Effectiveness and efficiency. Random reflections on…

The unconscious (Ucs)

Well this is either very simple or very complicated. I am a believer in…

Thought experiment (Gedankenexperimenten)

Exactly what it says! Some sort of experiment, i.e. an intervention with observed consequences, is…

Tidyverse

This is really just amusement but largely switching the way I use R from "base/standard…

More

Creation date lost, last updated 19.ix.26. Author CE; this page and all glossary contents are copyright to me so contact me if you want to quote from them (I’m sure I’ll agree!). That may change to a Creative Commons licence later when I am happier with the content.