Validity and Reliability of diagnostic test

Question 1

Validity

Answer 1

Ability of a diagnostic test to distinguish between who have the disease and who do not have the disease

Question 2

Sensitivity

Answer 2

Have the disease SNOUT - Rule out the disease, True positive rate

Question 3

Specificity

Answer 3

Distinguish those who do not have the diseae; True negative rate; Spin ; rule in the disease

Question 4

Reliability

Answer 4

Ability of the test result to produce the same result when repeated multiple times.

Question 5

Intra subject variation

Answer 5

• Intra-subject -Within subjects; same observers measures the same thing more than once

Question 6

Intra - observer

Answer 6

• Intra-observer - same observer measures the same thing more than once

Question 7

Inter observer

Answer 7

Inter-observer ; different observers measures the same thing

Question 8

Construct validity

Answer 8

“Are we measuring what we actually mean to measure?” (Construct validity)
* If we want to create a scale that measures happiness, are we really measuring happiness? Or
are we measuring extroversion? Or feeling energetic? Or enthusiasm? Or absence of
depression?

Question 9

Content validity

Answer 9

“Are we capturing the entire spectrum of the outcome?” (Content validity)
* If we want to rate mental health, is our scale capturing all aspects of mental health? Or just the
presence or absence of depression?

Question 10

Criteron validity

Answer 10

“Is the scale that we’ve developed correlated with the things that it should be?” (Criterion validity)
* Is there a correlation between emotional distress and loneliness? (Note: not necessarily a causal
relationship; any association may do)
* Is there an inverse correlation between age and mobility?

Question 11

Face validity

Answer 11

“Does this look right?” (Face validity)
* This is a subjective measure and one where you might not always want it (e.g. “Do you beat
your kids” may have face validity when it comes to determining child abuse, but probably will
not be answered honestly”)

Question 12

External validity

Answer 12

External validity or generalizable: the extent to which study findings
can be generalized or applied to populations, settings, and times,
other than those used in the study.
* Assessment of external validity:
* No simple formula
* Judgment, subject matter knowledge, population knowledge

Question 13

Internal validity

Answer 13

Internal validity: the extent to which a study accurately measures or
tests what is intended to be measured or tested
* A study without internal validity is not generalizable
* Therefore: internal validity is always more important