Introduction to outcome measures

Introduction to outcome measures for physiotherapy students

1. Introduction to Outcome Measures Dr Sreeraj S R

2. What are Outcome measures? Outcome measures are standardized tests, measures, or instruments used to measure various aspects of a patient’s health status. Results from outcome measures can be used for patient care decisions, research, and quality assurance. An evidence-based practitioner must consider the dimension, type, format, reliability, validity, responsiveness, and feasibility an appropriate outcome measure for their patient. 2 O’Sullivan.

3. Broad Classification Disease specific:   T end to measure more specific elements of the respective disease and are thus, theoretically, more sensitive to subtle treatment-related changes. Example: the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) in OA patient . Generic: T ypically assess the physical, social, and emotional dimensions of health and they tend to have the advantage of evaluating QOL for different type of diseases. Example: Short Form-36 ( SF-36 ), which generates a profile of eight dimensions in OA patient. 3 Wiebe S, 2003, Zeng Y., 2015

4. Dimension Outcome measures may be multiple dimensional or focused. An example for a multidimensional stakeholder-focussed evaluation approach is the “Tripartite Model of Mental Health and Therapeutic Outcomes which differentiates between the perspectives of (a) society, (b) the individual patient, and (c) the mental health professional. Region specific (e.g., Lower Extremity Functional Scale , Upper Extremity Functional Scale ), Disease, or condition specific (e.g., Western Ontario and McMaster Universities Arthritis Index), Patient specific (e.g., Patient Specific Functional Scale ), Global (e.g., Global Rating of Change ). 4 O’Sullivan, Outcome Measures [Internet]. Physiopedia . ‌

5. Format Outcome measures that we use in clinical practice are divided into four categories: Self-report measures Performance-based measures Observer-reported measures Clinician-reported measures 5 Outcome Measures [Internet]. Physiopedia . ‌

6. Self-report measures Patients respond verbally or in writing about their self-perception of some aspect of their health status. Patient-reported outcome measures (PROMs) are questionnaires measuring the patients’ views of their health status. Example: Health-related quality of life (HRQL) Patient-reported experience measures (PREMs) are questionnaires measuring the patients’ perceptions of their experience whilst receiving care. Example: CARE (Consultation and Relational Empathy ) measure questionnaire. 6 Kingsley C, 2017, Outcome Measures [Internet]. Physiopedia .

7. Performance-based measures ( PerfO ) These require patients to perform a task that is graded by the physical therapist. Scores for performance-based measures can be based on either an objective measurement or a qualitative assessment that is assigned a score. Example: Functional Independence Measure , which requires the patient to demonstrate self-care activities, transfers, locomotion, and bowel and bladder function. 7 Clinical Outcome Assessment [Internet]. Physiopedia . 2020

8. Observer-reported measures ( ObsRO ) Measurement based on an observation by someone other than the patient or a health professional. Usually done by patient's non-clinical care giver, family or anyone living around patient and observes the patient in daily life. Example: assessment of a patient's cognition. 8 Clinical Outcome Assessment [Internet]. Physiopedia . 2020

9. C linician-reported outcome measures ( ClinRO ) These are measurements that are completed by a health care professional. Based on the report that comes from a trained health care professional after observation of a patient's condition. Example: pain rating scale. 9 Clinical Outcome Assessment [Internet]. Physiopedia . 2020

10. Reliability The reliability of an outcome measure refers to its consistency or reproducibility. As the reliability increases, the amount of error inherent in the measurement decreases. Different types of reliability that affect outcome measures; Test-retest refers to the stability of measurements over time. Intratester and intertester reliability refers to consistency of repeated measures obtained by the same practitioner or between two practitioners, respectively. Reliability of continuous level data is calculated using intraclass correlation coefficients, whereas the kappa coefficient is used for categorical level data. Internal consistency refers to the degree in which similar items on an outcome measure yield similar scores and is represented by Chronbach’s alpha. 10 O’Sullivan.

11. Validity Validity is the degree to which an outcome measure is measuring what it purports to measure. For example, the degree to which the Berg Balance Scale is measuring balance. There are four basic types of validity: Face validity Content validity Criterion-related validity Construct validity 11 O’Sullivan.

12. Face validity Face validity, also called logical validity, is a simple form of validity where you apply a superficial and subjective assessment of whether your study or test measures what it is supposed to measure.    Example: IQ tests are supposed to measure intelligence.  12 Face Validity: Definition and Examples - Statistics How To

13. Content validity Content validity is how well an instrument (i.e. a test or questionnaire) measures a theoretical construct. Content validity uses a more formal, statistics-based approach, usually with experts in the field who judges the questions on how well they cover the material. 13 Content Validity (Logical or Rational Validity) - Statistics How To ‌

14. Criterion validity Criterion validity (or criterion-related validity) measures how well one measure predicts an outcome for another measure. Example: A job applicant takes a performance test during the interview process. If this test accurately predicts how well the employee will perform on the job, the test is said to have criterion validity. 14 Criterion Validity: Definition, Types of Validity - Statistics How To

15. Construct validity It demonstrates that the test is measuring the construct it claims it’s measuring. Example: a doctor testing the effectiveness of painkillers on chronic back sufferers. construct validity would test whether the doctor was measuring pain and not numbness, discomfort, anxiety or any other factor. 15 Construct Validity: Simple Definition, Statistics Used - Statistics How To, Shuttleworth M ‌

16. Reliability vs. Validity Reliability The consistency of measurement, or the degree to which an instrument measures the same way each time it is used under the same condition with the same subjects. Test-retest Internal consistency Validity The strength of our conclusions, inferences or propositions. Does it measure what it is intended to measure? Face Content Criterion Construct

17. References O’sullivan SB. Clinical Decision Making. In: Physical Rehabilitation. 6th ed. Philadelphia: F.A. Davis Co; 2014. p. 1–29. Wiebe S,  Guyatt G, Weaver B, Matijevic S, Sidwell C. Comparative responsiveness of generic and specific quality-of-life instruments. J. Clin. Epidemiol . 2003;56 (1): 52-60. Zeng Y., Zhou Y., Lin J., Zhou Y., Yu J. Generic and disease-specific quality of life and its predictors among Chinese inpatients with schizophrenia Psychiatry Res. 2015; 228 (3): 724-728 Outcome Measures [Internet]. Physiopedia . 2012 [cited 2020 Aug 9]. Available from: https://www.physio-pedia.com/Outcome_Measures#cite_note-5 Kingsley C, Patel S. Patient-reported outcome measures and patient-reported experience measures. BJA Education [Internet]. 2017 Apr [cited 2020 Aug 9];17(4):137–44. Available from: https://academic.oup.com/bjaed/article/17/4/137/2999278 Clinical Outcome Assessment [Internet]. Physiopedia . 2020 [cited 2020 Aug 16]. Available from: https://www.physio-pedia.com/Clinical_Outcome_Assessment ‌Face Validity: Definition and Examples - Statistics How To [Internet]. Statistics How To. 2015 [cited 2020 Aug 16]. Available from: https://tinyurl.com/y3qbk44c ‌ Content Validity (Logical or Rational Validity) - Statistics How To [Internet]. Statistics How To. 2015 [cited 2020 Aug 16]. Available from: https://tinyurl.com/y3e72dkl Criterion Validity: Definition, Types of Validity - Statistics How To [Internet]. Statistics How To. 2015 [cited 2020 Aug 16]. Available from: https://tinyurl.com/y3wcz726 ‌ Construct Validity: Simple Definition, Statistics Used - Statistics How To [Internet]. Statistics How To. 2014 [cited 2020 Aug 16]. Available from: https://www.statisticshowto.com/construct-validity/ Martyn Shuttleworth. Construct Validity - Does the Concept Match the Specific Measurement? [Internet]. Explorable.com. 2020 [cited 2020 Aug 16]. Available from: https://tinyurl.com/y3g7vxda ‌ 17