PT 521 EBP

Sensitivity

Proportion of patients with the target disorder who have a positive test result

Specificity

Proportion of patients without the target disorder who have a negative test result

specificity

True negative rate

sensitivity

True positive rate

out

When sensitivity is high, a negative test rules____________ (in or out) the disorder

in

When specificity is high, a positive test rules ____________ (in or out) the disorder

negative

When sensitivity is high, a ________________ (negative or positive) test rules out the disorder

positive

When specificity is high, a ________________ (negative or positive) test rules in the disorder

Positive Likelihood Ratio (+LR)

The likelihood that a given patient has the disorder

Sensitivity / 1 - Specificity

Formula for Positive Likelihood Ratio (+LR)

Negative Likelihood Ratio (-LR)

The likelihood that a given patient does not have the disorder

1 - Sensitivity / Specificity

Formula for Negative Likelihood Ratio (-LR)

LR+

With a large ______ (LR + or -), if the test is positive, the probability that the patient has the disorder increases markedly.

LR-

With a very small ______ (LR + or -), if the test is negative, the probability that the patient has the disorder becomes much smaller

LRs

can be used to estimate the pre to post test shift in probability

pre-test probability

the likelihood that a patients exhibits a specific disorder before the clinical examination is performed

Prevalence

The ______________ rate of the condition can be used as an indication of Pre-Test Probability

LR+ >10, LR- <0.1

Likelihood ratios interpreted as large and conclusive change from pre-test to post-test probability

LR+ 5-9.9, LR- 0.1-0.29

Likelihood ratios interpreted as moderate shift from pre-test to post-test probability

LR+ 2-4.9, LR- 0.3-0.59

Likelihood ratios interpreted as small but sometimes important shift from pre-test to post-test probability

LR+ 1-1.9, LR- 0.6-1

Likelihood ratios interpreted as small and rarely important shift from pre-test to post-test probability

Nomogram

Device used to examine LR between pretest and posttest probability

reliable

results can be repeated

validity

the extent to which a test measures or predicts what it is supposed to

true

True or False? A test can be reliable and not valid

True

True or False? If a test is valid it must be reliable

ratio, interval, continuous

Date to use with ICC values

ordinal, nomical, categorial

Date to use with ICC values kappa statistics

SEM (standard error of the measure)

Error associated with a single measure

MDC (minimal detectable change)

Error associated with the change score

MCID (Minimally Clinically Important Difference)

Amount of change which represents true change to the patient