Outcome Measures- Reliability and Validity Flashcards
OUTCOME MEASURES
OUTCOME MEASURES
Outcome measures can be both ________ and _________. List examples of each.
Objective
-ROM and length, Temp, Weight, Height, BP, HR, Strength
Subjective
-Pain, Intelligence, Health, Burnout
Measurement is the process of assigning _________ to variables to represent quantities of characteristics by rules. They are the actual results of implementing the ____ that indicate the impact on functioning.
- numerals
- POC
Very few variables are measured _________, most are not directly observable.
directly
________ as a _________ _________ are often cheaper and easier to measure than ‘true’ endpoints (ie. it is easier to measure a patient’s blood pressure than to use EKG).
biomarkers as a surrogate endpoint
What is a biomarker?
Objective, quantifiable characteristics of biological process
What is a surrogate endpoint?
A substitute for clinically meaningful endpoint
Psychometric properties to consider to make selection of right measures?
- Reliability
- Validity
- Scale of measurement
- Self-report vs. Performance-based measure
- Error parameters (minimal detectable change)
- Clinical utility of the measures
What are the 2 most important properties to consider before choosing measurement?
reliability and validity
Reliability = \_\_\_\_\_\_\_\_\_\_ Validity = \_\_\_\_\_\_\_\_\_\_
- consistency
- accuracy
_________ is an extent to which a measurement is consistent and free from error. It has consistency time after time with as little variation as possible.
Reliability
Many reliability coefficients are based on measures of correlation. What is correlation?
The degree of association between two sets of data
Draw a _______ plot to visualize correlation, and compute _______ _________ (r) to quantify it.
- scatter
- correlation coefficient
What are the 4 major types of reliability?
- ) Test-retest reliability
- ) Intrarater reliability
- ) Interrater reliability
- ) Internal consistency
What is test-retest reliability?
consistency of repeated measurements that are separated in time
What is intrarater reliability?
consistency of repeated measurements by the same PT practitioner at different times
What is interrater reliability?
- consistency of repeated measurements by multiple PT practitioners
- important to be good unless the usefulness of that test is limited
What is internal consistency?
consistency over multiple items or parts in a test, where each part is supposed to measure one, and only one, concept
_______ is the degree to which a test is measuring what it is intended to measure.
Validity
What are the 3 major types of validity?
- Face validity
- Content validity
- Construct validity
What is face validity?
- Does the content of the test appear to be suitable to its aims?
- the weakest form of the validity
- inspection of items for proper selections made by non-experts
What is content validity?
- Is the test fully representative of what it aims to measure?
- inspection of items for proper selections made by experts
What is construct validity?
- Does the test measure the concept that it is intended to measure?
- correlation and factor analysis to check
- What is the weakest form of validity?
- What is the strongest?
- face
- construct
What are the 4 scales of measurement in order based on their relative precision of assigned values?
Ratio -distance, age, time, decibals, weight Interval -calender years, C or F Ordinal -MMT, function, pain Nominal -gender, blood type, diagnosis