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: the way the search 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 title that is exactly the phrase you typed in to find is hidden down the list of suggestions.

If what 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!

O

Orthogonal contrasts

This is pretty technical but you might come across it in papers using analysis of…

Odds = odds ratio

At times in the past I have found the idea of "odds" and odds ratios…

Octile(s)

I confess this is me throwing one in for completeness, I don't think I've ever…

Observer-reported outcome measures (ObsROMs, OROMs)

My usual pedantry that we should be very careful about the word "outcome" here and…

Omitted variable

The is all about summer! OK, it's not generally but the classic explanation of how…

Orthogonal

Posh word meaning "at right angles to", "perpendicular to", "independent of" Details Can come up in a…

Open peer review

See peer reviewing. Dates Created 18.viii.23.

Opting out

More often termed "dropping out" or, mainly by researchers, "attrition". Used to refer to…

Open source software

OK, I admit it, this is mostly here to give a plug to the R…

Open access

A fundamental change in the academic publishing world that has exploded in the 21st Century….

More

Creation date lost, updated 19.v.24 to add the new BetterDocs “encyclopedia” listing of entries, tweaks 13.iv.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.