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!

M

MAPI trust

"Mapi Research Trust is a non-profit organization dedicated to improving patients’ quality of life by…

Mapping psychometric statistics to words: rules of thumb

This seems to me to be a particular feature of psychometrics: it loves rules of…

Marginalised client groups

Exactly what it says really. Why put it here when it's so obvious that it…

Markov/Markovian process

A time series concept, pretty technical but does come up in our fields. Details A Markov, or…

Maximum

This is an easy one! Just the largest value of a variable in any…

MCAR: Missing Completely At Random

Data are MCAR when there are no shared effects linking missingness on one variable and…

McDonald's Omega

Often contrasted with Cronbach's coefficient alpha, thus creating a lovely "alpha and omega" of internal…

Mean (arithmetic mean, average)

In colloquial language we use average to describe a norm or a “typical” set of…

Mean Squared Error (MSE)

What it says really: the mean of the squared deviation of a set of values…

Measure

In Counselling and Psychotherapy a measure generally refers to a standardised way of gathering data/information…

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.