The PSFS was originally developed by Paul Stratford, PT and his colleagues at McMaster University and has proven to be a quick and easy subjective outcome measure to use.
PSFS should be given during history taking in order to maximize the patient’s and the PT’s focus on function (“I have difficulty putting on my socks and shoes”) rather than focusing on just pain and impairments (“I am in a lot of pain when I bend my knee”).
The PSFS focuses on the patient’s opinion of their function, as a PT asks the patient to list three activities that are limited by their condition.
Can you tell me three important activities that you’re unable to do or are having difficulty with as a result of your XYZ problem? They should be activities that you are very motivated to do again.
1. I want to play golf again and walk the full course
2. I want to attend to and cut my lawn for 2 hours
3. I want to wash my dog (Max a British Bulldog)
How would you rate your ability to do ABC today?
0% is you can’t do it at all and 100% is you are perfectly able to do the activity at the same level as before your problem.
1. I tried golf 2 months ago and I was 50%
2. I can only garden for 20 minutes now so 20%
3. I would not even attempt to wash Max, I am 0%
My goal is to help you get to 100% in these 3 activities. I s that OK with you?
Disclaimer: I have taken the liberty of changing some aspects of the PSFS for my own clinical use with justifiable reasons. I appreciate that one cannot just haphazardly change already researched and validated outcome measures. Every day I live with the guilt!
The first change that I admit to is that I have altered the dialogue, to make it less formal.
Secondly, although the PSFS has been validated with the 0-10 scale, I prefer to use the percentage scale as I have noticed that patients find percentage easier to understand and rate. 0% is unable to perform and 100% is able to perform the activity at the same level as before the problem.
A pain score of ten is “bad” whereas zero is “good”. On the other hand, in original PSFS a functional score of ten in is “good” and zero is “bad” which some find confusing. To eradicate the confusion in scales, patients seem to clearly understand being 100% functional at something is always good!
Stratford PW, Gill C, Westaway M, Binkley JM. Assessing disability and change on individual patients: a report of a patient-specific measure. Physiotherapv Canada. 1995;47:258-263.