**Clinical Decision
Support Systems**

**Practice Questions**

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1.
Decision support tools for clinical consultation __do not__ generally
require

a. a systematic vocabulary and syntax for
machine representation of medical information

b. a medical knowledge base and means of routinely updating it

c. the ability to process patient data of varying degrees of
completeness

d. an "inference engine" based on logical deduction

e. the ability to express the "reasons" supporting their
recommendations

2.
In principle, expected value decision making assumes all but which of the
following?

a. all outcomes relevant to making the decision
may be represented numerically

b. any relevant outcomes that are qualitatively different (e.g.
death vs. severe pain) may nevertheless be reexpressed and compared on the same
numerical scale

c. physicians and patients are in generally close agreement on the
utilities of different outcomes

d. a decision that produces the highest benefit, on the average
over all patients, is better than a different decision that protects the most
patients against the worst result

e. a decision that produces the highest benefit, on the average
over all patients, is better than a different decision that produces the best
result for the most patients

3.
In the context of medical decision analysis, sensitivity analysis refers to

a. evaluating the sensitivity of a diagnostic
laboratory test used in arriving at the decision

b. using the sensitivity of the laboratory test in Bayes' Theorem
to calculate the positive predictive value of a diagnostic laboratory test
result, for use in arriving at the decision

c. using the sensitivity of the laboratory test in Bayes' Theorem
to calculate the negative predictive value of a diagnostic laboratory test
result, for use in arriving at the decision

d. determining how large a change in the assumed sensitivities of
any diagnostic tests used in arriving at the decision, changed individually or
in combination, is necessary to produce a change in the recommended decision

e. determining how large a change in each of the assumed
parameters of a decision analysis, changed individually or in combination, is
necessary to produce a change in the recommended decision

4.
Appendicitis is suspected in a 15 year old boy with right lower quadrant pain
persisting for 2 days with increasing severity, anorexia, no nausea or
vomiting, 2 loose stools/day, rectal temp 38C, normal urinanalysis, and WBC
15,000 with left shift. Assume that with these signs and symptoms
the probability of appendicitis is 30%, that operative mortality for
appendectomy is 0.1%, and that when surgery is delayed until the appendix perforates
the mortality is 1%. Now sSuppose that a non-invasive diagnostic test, with
sensitivity of 70% and specificity of 90%, were available for appendicitis. The
test is inexpensive, and quick enough that there is negligible risk associated
with delaying long enough to get the result. Should a physician aiming to
minimize mortality perform the test? Justify your answer.

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