Choosing a therapy outcome measure that’s right for our practice, with our clients, in our settings, isn’t something that we should leave to chance. The choice, however, can sometimes be bewildering, even overwhelming. Here is some guidance and a few simple rules that may help.

In this blog I attempt to provide some guidance on the process of choosing a measure of therapy outcome that’s right for you. I hope it will be helpful whether you are considering this area for the first time or are looking at alternatives to measures you use already.

I’m going to briefly cover some key but often overlooked basics, such was ‘What do we mean by outcomes?’ and ‘What is an outcome measure?’ I will also outline a number of key criteria that you should consider when selecting any outcome measure. In addition, I’ll highlight some key categories of measure such as global distress and condition specific measures, and key features of some of the more commonly used measures in the UK. Finally, I’ll tell you where you can go for more detail or to lay your hands on the measures themselves.

Without further delay:

What is an outcome, and what is an outcome measure?

In defining an outcome, I’ve deliberately not looked for a dictionary definition nor one from the psychotherapy research literature. In relation to my own practice, I feel pretty clear what an outcome is, and I don’t want to get pulled down any rabbit holes. This is my definition:

In psychological therapy an outcome is a material difference in an aspect or aspects of the client’s circumstances that comes about during therapy.

If that sounds a little vague, that’s because there are many caveats I can apply to the statement. Outcomes in therapy may take many forms: improved wellbeing or self-regard; reduction of symptoms or problems, improvement in life or social functioning; achievement of goals; overcoming obstacles or long-standing patterns of self-defeating or destructive behaviour; acceptance; contentment; letting go. The list could go on and on.

The key point is that the ‘outcome’, whatever that may be, comes about during the process of therapy. Note that I’m not saying ‘as a result’ of therapy, simply during therapy.

Not all outcomes will be linked to therapy goals. Clients start and end relationships, lose loved ones, and suffer health crises. They have lives outside of therapy. Hence, while some outcomes may be the result of the deliberate focus and actions of client and therapist, others may be a by-product or completely unrelated.

Finally, while we generally tend to think of outcomes in a positive sense, some outcomes of therapy may be negative. Not everyone benefits from therapy, and in the worst cases, one or more parties may be harmed.

What is an outcome measure?

Quite simply, it is an instrument that seeks to measure the degree of change in a defined outcome, such as one of those outlined above. Note that I’m not saying, ‘the degree of change in a defined outcome brought about by therapy’. The argument over whether or not it was the therapy that made the difference is one which has lost us many a forest to paper, and I’m not going there today.

For the rest of this blog, I’m referring to standard measures that have gone through a process of testing to determine what’s known as their ‘psychometric properties’. These include properties such as their usability, reliability (i.e. sufficiently free from random error) and validity (i.e. measuring what they claim to). I’m not referring to bespoke or home-grown measures.

How to choose an outcome measure

While choosing an outcome measure that’s right for you should be a considered process, it needn’t be complex. Being as clear as you can about the six areas outlined below should help to steer you towards an appropriate measure or measures. There is always a balance to be struck in determining which measure or measures are appropriate. Think about how and where you intend to use them. Longer measures, for example, will elicit more information which could be useful at the assessment stage. Will the same measure, however, be feasible to use for tracking client progress session by session? These are some of the important areas to consider:

What are you trying to measure?

Start with your purpose and align your measure to that. For example, do you want your measure to inform your assessment process or are you simply wanting a general indication of the clients’ psychological ‘temperature’? Do you want to capture clients’ general or global distress or symptoms, or more specific symptoms or conditions (e.g. anxiety, depression or trauma)?

In some cases, it may be appropriate to use more than one measure. A consortium of services that I work with, for example, use both CORE and the Impact of Events (IES) scale with clients who have experienced sexual abuse or violence. My rule of thumb is don’t collect data just because you can, and generally ‘routinely one measure, exceptionally two.’

Does the measure have scientific credibility?

A lot of research goes into testing measures for qualities like validity and reliability. A little research on your part should help to establish that any measure you are considering fits the bill and is free of serious shortcomings. I’ll say a little more on that later and in the next blog.

Is it suitable for your client group?

Will the measure be easy for your client group to understand and complete? Some measures have versions that are adapted for use by children and young people, or people with learning disabilities.

Is it feasible to use in routine practice?

Is the measure short enough to use as part of your assessment, yet detailed enough to give you the detail you require? Are there shorter versions, so that even if you use a full version at assessment you can easily use the shorter version if you want to track clients’ progress  through therapy. Is it easy enough for you or your practitioners to score and understand what the numbers mean, and to discuss this with clients?

How widely used is it?

Is the measure widely used in your sector or setting? If you work in or manage a service, do similar services use the same measure? Is the measure one which is recognised or mandated by service commissioners? Are local or national benchmarks available which would enable you to compare your data with others?

Bespoke or home-grown measures may have their place if there are particular elements of your practice you wish to capture. Otherwise I wouldn’t usually recommend their use.

Is there a cost to its use?

Is there a cost to using the measure? For most purposes and most conditions there are both measures that require payment of a licence fee, and those that are free. If you wish to use the Beck’s Depression Inventory (BDI), for example, the manual and 25 forms will set you back £108. [i] The Patient Health Questionnaire (PHQ9), by contrast, is free to use in most circumstances.

Where can I go to find out more?

In the next blog I’ll be reviewing a clutch of measures commonly used in therapy: one a global measure of distress (CORE), two condition specific (GAD7 and PHQ9), as well as an ultra-brief four item measure (the Outcome Rating Scale). I’ll be looking at their relative strengths and shortcomings and how they can be used within our practice.

If you want to survey the options more widely, I can recommend an outcomes compendium produced by the former National Institute for Mental Health in England. [ii]  Despite being published in 2008, and to the best of my knowledge never having been updated, it remains a comprehensive resource. The information it contains is well presented and includes details of the cost and key characteristics, as well as an evaluation of the psychometric properties of nearly 200 measures.

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Posted by:Barry McInnes

2 replies on “How to choose a therapy outcome measure

  1. Thank you so much this article was so Intresting helpful in making me understand outcome measures. Is there a name to the 6 points to choosing an out come measure?

    1. Hi Lydia. Thank you so much for your comment and I’m delighted you found the article helpful. The six points are all our own, so they have no name as such, unless you’d like to suggest one!

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