NR503: Population Health, Epidemiology, & Statistical Principles
Week 2: Epidemiology and Biostatistics to Inform Advanced Practice
Nursing
TD3: Please provide a summary of the case or information you have
discussed
...
NR503: Population Health, Epidemiology, & Statistical Principles
Week 2: Epidemiology and Biostatistics to Inform Advanced Practice
Nursing
TD3: Please provide a summary of the case or information you have
discussed this week
The ability to classify individuals into the correct disease status depends on
the quality, and accuracy of the screening or the diagnostic test. Ideally, a
good screening test will be able to tell us which subjects have the disease
and vice versa, which will lead to earlier treatment and that this, in turn, will
lead to a better outcome. The ideal screening test must also be valid and
reliable. The validity of a test is defined as its ability to distinguish between
who has a disease and who does not (Gordis, 2014 p, 88). An ideal screening
test is exquisitely sensitive (high probability of identifying correctly those
who have the disease) and extremely specific (high probability that those
without the disease will screen negative). If a test is reliable, it gives
consistent results with repeated tests.
When evaluating the feasibility or the success of a screening program, one
should also consider the positive and negative predictive values. Positive
predictive value is the proportion of persons with a positive test that are true
positive actually have the disease (true positive) whereas negative predictive
value is the proportion of those who test negative who do not have (Gordis,
2014 p, 100). Predictive value of a test is an important issue. Physician used
it to enhance his/her ability to make a correct diagnosis. One needs to
consider what happens to the people who had a positive screening test but
turned out not to have the disease (false positives) and to the people who
had a negative screening test but turned out to have the disease (false
negatives).
Reference
Gordis, L. (2014). Epidemiology (5th ed.). Philadelphia, PA: Elsevier
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