Psychometrics

Understand the application of measurement to Evidence-Based Practice (EBP) in rehabilitation:
- Importance of measuring health outcomes to support EBP.
Become familiar with different types of outcome measures used in rehabilitation:
- Understanding various measurement tools.
Comprehend terminology and metrics used to assess a measure’s psychometric properties:
- Grasping fundamental terms related to measurement accuracy and reliability.
Identify constructs that align with the use of rehabilitation measures:
- Recognizing key constructs, like function and quality of life.
Describe motivations for and challenges with measurement in rehabilitation:
- Understanding the reasons for measurement and potential obstacles.

Health conditions are complex and multidimensional:
- Rehabilitation often deals with overlapping health issues.
Many aspects of health and functioning can be impaired simultaneously:
- Patients may experience a range of simultaneous impairments.
Symptoms are often variable:
- Patient experiences can differ greatly.
Conditions/symptoms may last a lifetime:
- Chronic conditions necessitate ongoing assessment.

Patient goals can be specific or very broad:
- Tailoring rehabilitation to address individual patient needs.
Achieving goals often requires interdisciplinary expertise:
- Involves collaboration across various health professionals (e.g., PT, Doctor, OT).
Goals can change over time:
- Adjustments may be necessary depending on patient progress.

Enables patients to see measurable changes:
- Visualization of progress can motivate recovery.
Facilitates patient-practitioner communication:
- Improves patient engagement and understanding of their own health.
Increases health literacy:
- Patients become more informed about their conditions and treatments.
Provides a foundation to discuss details of a patient's recovery:
- Data-driven discussions enhance care.

Describe patient functioning:
- Tools assist in capturing patient capabilities and challenges.
Assist in justifying provision of care:
- Justification for specific treatments based on measurable outcomes.
Help guide appropriate interventions:
- Indicates when referrals or other actions may be necessary.
Examine effectiveness of treatment:
- Baseline measures assist in comparing outcomes to normative data.

Contribute to standards of practice:
- Helps in developing clinical practice guidelines (CPGs).
Demonstrate professional autonomy:
- Moves practitioners from being viewed merely as “technicians.”
Evidence of treatment efficacy:
- Supports the overall credibility of rehabilitation practices.
Contribute to patient registries:
- Data collected can aid in broader research efforts.

Function:
- Most common and straightforward measure, focusing on physical capabilities such as mobility, balance, strength, range of motion (ROM), endurance, and return to sport.
Health:
- Includes symptoms experienced by patients (e.g., pain, sleep disturbances).
Quality of Life:
- Encompasses physical, mental, social, and environmental health aspects.

Patient-Reported Surveys:
  - Measure patients' perceived ability/disability.
  - Strengths:
    - Quick and inexpensive to administer.
    - Scalable for larger samples; easy to score and analyze.
    - Reduces bias.
  - Limitations:
    - May be influenced by factors like comprehension and cognitive abilities.
    - Susceptible to recall bias.
Performance-Based Tests:
  - Assess actual ability through task performance in a controlled environment.
  - Strengths:
    - Higher face validity; considered more objective.
    - Less affected by linguistic or educational background.
  - Limitations:
    - Often do not encompass all aspects of performance.
    - Demand more resources and may not reflect real-life conditions.

Generic Instruments:
  - Designed for a wide range of health conditions, including general health aspects.
  - Benefits:
    - Comparative use across diverse conditions, often containing normative data.
  - Limitations:
   - May lack sensitivity to unique issues pertinent to specific populations.
Condition-Specific Instruments:
  - Tailored to specific groups or conditions with a focus on relevant issues.
  - Benefits:
    - Greater precision in measuring relevant constructs; sensitive to changes over time.
  - Limitations:
    - Less generalizable beyond specific conditions.

Application: Assess patient status, evaluate changes over time, and study intervention effects.
- Example: Evaluating endurance with the 6-minute walk test.
Key Psychometric Properties:
- Convergent construct validity, test-retest reliability, measurement error sensitivity.

Goal: Classify or group individuals based on health status (e.g., low back pain).
- Key Psychometric Properties:
- Known groups validity, concurrent criterion validity.

Goal: Diagnose conditions and anticipate outcomes (e.g., fall risk).
  - Example: Using the Berg Balance Scale to predict fall risk.
  - Key Psychometric Properties:
    - Predictive criterion validity.

Time Constraints:
- Administrative preparation and scoring.
Space & Equipment:
- Need for adequate space and specialized equipment.
Personnel & Training:
- Requirements for training and protocols for administration.
Cost:
- Equipment and permissions may incur additional costs.

Reliability:
  - Reproducibility of scores; consistency of the measure.
  - Types of Reliability:
    - Intra-rater reliability
    - Inter-rater reliability
    - Internal consistency
    - Test-retest reliability
Validity:
- Accuracy in measuring the intended construct. Reliability must be confirmed for validity.

Face Validity:
- Extent to which a test appears to measure what it's intended to measure.
Content Validity:
- Comprehensive representation of the construct in the tool.
Construct Validity:
- Extent to which a theoretical construct is represented.
Criterion-Related Validity:
- Determining the relationship of the measurement with a gold standard.

Known Groups Validity:
- Ability to distinguish between distinct groups having different levels of a construct.
Convergent Validity:
- Correlation between tests measuring the same construct.
Discriminant Validity:
- Low correlation between tests measuring different constructs.
Concurrent Validity:
- Agreement level with a gold standard measure.
Predictive Validity:
- Forecasting of future events based on the measure.
Prescriptive Validity:
- Suggesting treatment based on measure outcomes.