BOOKS OF RtfiDIfGS - PAHO/WHO

- 131 -
A \ ,,1. XIX, No. 3 PEHFOHRMANCE ASSESS. iE.' l
con"sumer %will pass successfully through
multiple successive elemnents of care can
be obtained directly from the number of
individuals in the study cohort who suc-
.essfully completed the sequence, but also
can be calculated as the product of the intervening
probabilities."a Thus the
"continuity-of-process index" of Table 4
expresses the probability that a paitient
screened positive (in this case for either
anemia or a urinary tract infection) will
achieve contact with the system, have the
problem recognized, receive tre' Rnent,
make contact for follow-up, have the need
for followv-up recognized, and receíive the
followv-up servnice. As shown in Table 4,
this probability ranges ftomr 0.55 in Service
Unit C to 0.09 in Service Unit E. The
aggregated results suggest that the three
Sc'rvice Units have three distinct pattems
of care. Service Unit C, with a continuityof-process
index of 0.55 for treatmnent and
follow-up, appears to have no particular
step in the process of care which stands out
as a relative deficiency. Service Unit D,vwith
a continuity-of-process index of 0.36,
is similar to Service Unit C except for recognition
(indicators 2 and 5), which appears
as the relative impediment. Service
Unit E, with a continuity-of-process index
of only 0.09, appears to have substantial
deficiencies in both contact (indicators 1
and 4) and recognition (indicators 2 and 5).
The next step in the analysis would be to
determine if these distinctions continue
1when the results are disaggregated and
examined by1
tracer.
" Care must be taken in multiplying together PU's
olt.iii< .d fromn different tracer conditions and different
cohorts, because patients recciving adequatet cwrt
early in the process of care may not be independent of
those receiving adequate care later on. Specifically,
patients receiving adequate care at one stage may also
he more likely to receive adequate care at another. In
fact, such nonindependence is illustrated in the data
reported by Novick,'° although it was not explicily
pointed out by him. We have avoided this problem by
calculating continuity-of-process scores only for functicns
or sequences offiunctions where we were able to
ob.serve the passage of the cohort throughout the sequence.
Thus, our continuity-of-process scores are
observed, not calculated. When greater knowledge is
obttaiued about the interdependence of functions we
may be able to combine continuity-of-process scores
ohbtained from different cohorts.
The assessment method can also
examine the distribution of care among
various types of consumers, with one ofthe
most useful distinctions being consumers
at different risk to particular health problems.
In a study of prenatal care at one IHS
service unit, 22 of 50 pregnant women in
the study cohort were classified as high risk
becaus(e they were under the age of 18
years, over the age of 35 years, primigravida,
with parity equal to or greater than
5, or with a history of miscarriage or spontaneous
abortion, while the other 28
women were classified as average risk.
Table 5 shows results for three indicators
(of the 25 employed in the study) which
constitute a simple se(luence to examine
the continuity of process of gonorrhea
screening. Respectively, the indicators
examine the proportion of women achiesing
contact itl the systemni by the 20th
gestational week, the proportion of those
with pregñiancy recognized by the 20th
week, and the proportion of those having a
= cervical culture by the 20th gestational
week.
As is apparent from the indicator results
and continuity-of-process index of Table 5,
system performance favors the average risk
group at each step of the process. The reasons
for the disparity are suggested by the
encounter-based indicators for pregnancy
recognition and gonorrhea screening disaggregated
by site of contact as shown in
Table 6. Unlike population-based indicators,
encounter-based indicators are
computed in units of patient encounters
with the system. Thus, only 43 per cent of
encounters by high-risk patients compared
with 67 per cent of encounters by averagerisk
patients due for recognition of pregnancy
resulted in pregnancy recognition.
Similarly, only 33 per cent of encounters
by high-risk patients compared with 71 per
cent of encounters by average-risk patients
with pregnancy recognized and due for
gonorrhea screening received a cervical
culture. When disaggregated by site of contact,
the results suggest that the prenatal
clinic performs well in both the recognition
and screening function, the public