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!

I

Idiographic measure, Idiographic methods

An idiographic measure gives a picture (“graphic”) unique to the individual (“idio”). For example, a…

Idiographic vs. nomothetic: history

There are separate entries (see "try also") for idiographicm, sometimes spelled "ideographic", and nomothetic measures,…

Imputation

No, not when someone imputes malevolent intention to your attempt to help! In research…

Independence of observations

This is an absolutely fundamental aspect of all statistical methods: the idea that all the…

Independent variable

Term sometimes used for Predictor variable when looking at the relationship with a Dependent variable….

Inferential testing, "tests"

This approach to evaluating findings starts out with an idea that it is worth investigating…

Informed consent

When we seek consent from our clients for participating in a treatment or in a…

Intention to treat (ITT) analyses

You may come across this in reports of controlled trials of therapies (or of anything…

Inter-quartile range (IQR)

[see quartiles!] The “interquartile range” is the distance between the 25th centile (the score such that…

Inter-rater agreement/reliability

One way to assess how good, how usable, a rating system is is to get…

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.