BOOKS OF RtfiDIfGS - PAHO/WHO

NUTTING ET AL.
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for the tracers as a group is similar to all
care, and assumes that efforts that improve
deficient care in the tracers will also improve
care for other similar conditions, although
these assumptions are not yet supported
by experimental evidence.
Consistent with Kessners use of tracers
in sets, rather than singly, the assessment
aggregates data by function across the tracers,
in order to focus corrective action on
function rather than disease.** The funetions
we have used-prevention, screening,
health status monitoring, diagnostic
evaluation, treatment planning, follow-up
and ongoing management-can be recombined
to fit the needs of a particular
analysis. Other functions, such as patient
education or rehabilitation, can be defined
if desired.
Most functions can be separated into
three sequential events, namely, contact
between a consumer and a provider, recognition
of the need for service once contact
is made and provision of service after
contact and recognition. Th ' particular'
classification of functions and sequential
events was chosen because it is generally
familiar, because the adaptive processes
required to correct deficiencies would appear
to differ by funetion and event, and
because the Indian Health Service may be
in a position to influence these categories
'* The data for a particular function are aggregated
by 1) summing the number of consumers found to be
in need of care in the study cohort of each one of the
tracers; 2) summing the number found to be receiving
adequate care in all tracer cohorts; and 3) dividing the
second sum by the first to obtain the fraction of consumers
for all tracers who are receiving adequate care
for that function. This procedure weights the tracers in
proportion to the size of their cohorts. Usuallyfthe size
of the cohorts have been in proportion to the prevalence
of the tracers, that is, the number of consumers
in need ofcare for each function of atracer, although in
some cases cohort sizes for all tracers have been equal.
The aggregating procedure assumes that when the
racers are weighted in proportion to cohort size, the
care received for the tracers is representative of the
care received for all health conditions. However, our
experience indicates that this assumption is not always
justified and that care should be taken in interpreting
aggregated results.
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MEDICAL CARE
of activities. This classification may be altered
as more experience is gained with
pattems of homogeneity across tracers and
with their usefulness in improving care.
When carrying out a particular assessment,
we define an assessment spacet
that is delineated by the functions, tracers,
systemn components and populations to be
studied. By defining the assessment space
and measures of performance first, the assessment
focuses only on issues of interest.
Table 1 shows the functions and tracers
that we used in early applications of the
assessment method. Every function is
examined using at least two tracers, by aggregating
the data across the tracers for
each function. This particular assessment
space was constructed to examine common
issues in ambulatory care, and did not address
care for mental health problems,
medical or surgical problems requiring
specialized care, or rehabilitation. Since
many of the functions are further broken
down into the three sequential events of
contact, recognition and provision of required
service, the assessment space permits
analysis of patient utilization, system
outreach and problem recognition. However,
this assessment space does not allow
for analysis of inappropriate utilization of
inpatient or outpatient services, surgical
procedures or inappropriate drug therapy.
For each tracer, minimal criteria for the
process of care are established for each
function which the tracer examines. In no
case was a tracer used to examine a function
for which "valid" criteria were unavailable
or for which the criteria originally
proposed were questioned by the local
providers of care. Only criteria considered
essential for basic health care are included.
Criteria that may apply to a relatively small
percentage of instances are useful in de-
tt The assessment space for a particular assessment
is defined by specifying 1) the functions tobe studied;
2) a set of tracers for each function; 3) the components
of the health system for each finmction; and 4)a population
of consumers (from which an appropriate sample
is selected) for each function of each tracer.