BOOKS OF RtfiDIfGS - PAHO/WHO

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Vol. XIX. No. 3
- 127 -
tant for prevention, scree¡inxg and health
status monitoring. As an example, a cohort
of women may be selected for examination
of prenatal care by generating a master list
from delivery room logs, birth certificates,
operating room logs and laboratory logs
(searching for prenatal lab work ordered).
W)hen the redundancies are removed from
the master list, a standard sampling
technique is used to select the study
.,e-,. For r any tracers a single document
!¡zly b'e lusctd t.. gt'ler.ltte' age- andaor
sex-specific study cohort. - g., birth certificates
alone may suffice for the generation
of a cohort for examination of infant care.
It also is important to sample from the
most basic source docunient available. For
example, in generating a cohort of patients
with urinary tract infections, it is better to
sample the líaboratory log for patients with
a positive urine culture than to generate a
sample of medical records for patients who
were diagnosed with a urinary tract infection.
The latter technique biases the sam- _
ple in favor of patients who have made
contact and for whom the system has recognized
the problem.
Patients are eliminated from the study
cohort when they do not contribute to the
objectives of the study. For example, when
examining uncomplicated urinary tract in-
.fections, it might be preferable to eliminate
patients with chronic urinary tract infections,
chronic renal disease, urinary tract
anomalies, etc. These characteristics become
apparent in the record review and
patients thus eliminated from the study
cohort may be replaced from the master
list.
Selection of the health records to be
examined largely defines the scope of the
medical care system to be examined. Since
medical care systems usually are not
clearly delineated, judgment is required to
define the system in a way that will produce
useful assessment results. Most assessments
of IHS Service Units' must
examine medical records at the main
PERFORMA.NCE ASSESSMESNT
FIG. 1. A sequence of population-based indicators
for urinary aert infections constructed to examine
the continuity of the process of care.
hospital-outpatient facility and at one or
more field clinics, public health nursing
records, medical records at one or more
referral centers and sometimes health records
from tribal health programs (e.g., nutrition,
mental health or alcoholism). In
applications of the method outside the Indian
Health Service, a similar set of record
types have been included in the assessment
procedure. In an assessment of one
rural private practice, records were
examined from two private practices, the
community hospital, the county health
clinic and the county public health nursing
program.
Audit instruments are designed for each
tracer to extract data from each record for
each individual in the study cohort. The