Research and Statistics Flashcards
(46 cards)
Nominal
Labels, mutually exclusive, exhaustive
Ex: male and female
Ordinal
Rank ordering, distance between rating not equal
Ex: 1st, 2nd, 3rd place in a race
Interval
Equal intervals between ratings, no true zero point
Ex: temperature
Ratio
Equal intervals, has true zero point
Ex: 10MWT
Reliability
Consistent and dependable- results can be reproduced under same conditions
Random errors limit reliability
Systematic errors limit validity
Data must be reliable before it can be considered valid
SEM
Repeated measures on the same instrument tend to be distributed around the “true” score
Large SEM = low reliability
Small SEM = high reliability
Ex: BP readings 120, 140, 160 vs. 102, 104, 106
Validity
The extent to which a test measures what it is purported to measure
A test must be reliable to be valid - although a highly reliable test may be invalid
Ex: bull’s eye with x’s
Construct Validity
How well a test measures the concept it was designed to measure
Ex: pain, intelligence, QoL
Content Validity
Assesses whether a test is representative of all aspects of the construct
Usually refers to surveys/questionnaires
Ex: QoL outcome measures
Criterion-related validity
Compares a test with other valid measures- gold standard
Concurrent- measures done at same time yield same results
Predictive- comparison btw the test and another measure administered in the future
Floor Effect
A measure’s lowest score does not capture patient’s level of ability
Ex: FGA has a floor effect for complete SCI
Ceiling Effect
A measure’s highest score is unable to assess a patient’s level of ability
Ex: FIST to young athletes post concussion
Minimal detectable change
The minimum amount of change in a patient’s score that ensures the change is not the result of measurement error
Minimal Clinically Important Difference
The smallest amount of change in outcomes that might be considered meaningful to patient/clinician
Sensitivity
True positive rate
How good a test is at determining who has the disease- test is positive for those who have the condition
A test with high sensitivity can be used to r/o the disease–
SnNout it out
SenSitivity = Screening
Specificity
True negative rate
A test that is good at finding those who do not have the condition
How often a test gives a negative result when the person does not have it
High specificity = can Spin it in
SpeCificity = Confirming
Positive Predictive Value
Percentage of people who are positive on the diagnostic test who have the condition
Ex 100% of people with vestibular disorder test (+), then high positive predictive value
Negative Predictive Value
Percentage of people who are negative on the diagnostic test who do not have the condition
Positive Likelihood Ratio
Indicates how many times more or less likely a positive test result will occur in someone with the condition than in someone without the condition
True positive rate compared to false positive rate
> 10: large, often conclusive likelihood disorder is present
5-10: moderate likelihood disorder is present
2-5: small likelihood disorder is present
1: normal (useless test)
Negative likelihood ratio
Indicates how many times more or less likely a negative test result will occur in someone without the condition than in someone with the condition
True negative rate compared to the false negative rate
1: neutral (useless test)
0.2-0.5: small decrease in likelihood of the disorder
0.1-0.2: moderate decrease in likelihood of disorder
<0.1: large, often conclusive decrease in likelihood of disorder
Mean
Sum all scores and divide by number of scores
Best used with interval/ratio data (unskewed)
Mode
The scores which are most frequently represented
Best used with nominal data
Median
Middle score for a set of data
Best used with ordinal data, skewed interval/ratio
Range
Difference between the highest value and the lowest value
No insight into distribution of scores
