Are the results of this economic evaluation valid?
The number of published economic evaluations is growing.2
However, many experts in the field have questioned the
methodological rigour of these evaluations.3 4 Therefore, it is
important for nurses to be able to assess the validity of the
methods used in these economic studies in order to determine
which findings they will apply to their setting.
All rigorous economic evaluations consider the opportunity
cost; that is, the value of the benefits foregone in alternative uses
when a resource is used for a given purpose.5 For example, the
opportunity cost to a municipality’s health department of funding
a community health screening programme for the elderly
may be the foregone benefits of not being able to fund a prenatal
programme for at risk pregnant women. In addition,
economic evaluations should consider the extra (ie, incremental)
benefit that would be gained for the extra (ie, incremental)
cost. A classic example illustrating incremental cost and effectiveness
is the sixth stool guaiac test used to screen for colorectal
cancer in people over 40 years of age. In the US, the average cost
per case of cancer detected using ≤ 5 tests has been calculated to
be US $2541, but the incremental cost of the sixth test was estimated
to range between $47 and $127 million.6 This is because
the probability of detecting an additional case of cancer (the
incremental effectiveness) is so low that millions of dollars (the
incremental costs) would be spent before identifying one more
person with cancer.