About the Patient-Specific Functional Scale
The Patient-Specific Functional Scale (PSFS) is a patient-centred outcome measure that allows you to identify and rate the difficulty of specific activities that are important to you. Unlike standardised questionnaires, the PSFS lets you choose activities that matter most to your daily life, making it a highly personalised tool for tracking your functional progress over time. This approach helps your healthcare team understand your unique challenges and measure meaningful improvements in activities that directly impact your quality of life.
Medical Specialties
Anatomic Areas
Clinical Indications
Developer Information
Developed by Paul W. Stratford, Carolyn Gill, Michael Westaway, and Jennifer Binkley in 1995 at McMaster University, Ontario, Canada. First published in: Stratford P, Gill C, Westaway M, Binkley J. Assessing disability and change on individual patients: a report of a patient specific measure. Physiotherapy Canada. 1995;47(4):258-263.
Copyright & Licensing
The Patient-Specific Functional Scale is in the public domain and freely available for clinical and research use without licensing fees or copyright restrictions. It may be used, reproduced, and modified without permission.
Administration Instructions
List up to 5 activities important to your daily life that you find difficult due to your condition. Rate each activity from 0 (unable to perform) to 10 (same level as before your injury).
Scoring Methodology
Patients identify up to 5 activities that are important to them and that they find difficult due to their condition. Each activity is rated on an 11-point numerical scale from 0 to 10, where 0 represents "unable to perform the activity" and 10 represents "able to perform the activity at the same level as before the injury or problem". The individual activity scores can be averaged to produce an overall functional score ranging from 0 to 10. Higher scores indicate better functional ability. The scale can be administered at multiple time points to track changes in function over the course of treatment.
Meaningful Change Threshold
A change of 2 points or more on an individual activity is considered the minimal clinically important difference (MCID). For the average score across all activities, a change of 2 points is also considered clinically meaningful. This threshold indicates a significant change in the patient's functional ability that is noticeable and relevant to their daily life.
Score Interpretation
Understanding what your score means
unable
0Unable to perform the activity at all due to the condition.
poor
1 - 3Severe functional limitation. Significant difficulty or inability to perform important activities.
moderate
4 - 6Moderate functional limitation. Notable difficulty performing important activities.
good
7 - 8Mild functional limitation. Able to perform most activities with slight difficulty.
excellent
9 - 10Minimal to no functional limitation. Able to perform activities at near pre-injury levels.
Clinical Limitations & Considerations
The PSFS has several limitations to consider: (1) Floor effects may occur when patients identify activities they are already unable to perform, limiting the ability to detect further functional decline. (2) The individualised nature of the scale means scores cannot be directly compared between patients, as each person rates different activities. (3) Some patients may find it challenging to rate activities on a numerical scale or may select activities that are too broad or vague. (4) The scale relies on patient self-report and subjective perception, which may not correlate perfectly with objective functional measures. (5) Cultural or language differences may affect how patients interpret and use the rating scale.
Supporting Literature
Key validation and development studies for the Patient-Specific Functional Scale
- 1
Assessing disability and change on individual patients: a report of a patient specific measure
Stratford PW, Gill C, Westaway M, Binkley J
Physiotherapy Canada, 1995
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This questionnaire is provided free of charge. Patient Watch charges only for platform services (data storage, automated reminders, analytics) - not for use of clinical instruments. This non-commercial model supports academic and clinical use. View full licensing disclosure