EPIDEMIOLOGY EXAM
gates.colby
he3383_exam2_f14_equationssheet.docHE 3383
Fall 2014
Exam #2
Chapters 4-5-6
Equations you may use for EXAM #2
n
10
period
time
same
the
during
risk
at
Population
period
given time
a
during
occuring
cases
New
Rate
Incidence
´
=
n
10
persons
all
for
totalled
observed;
person
each
Time
period
n
observatio
during
cases
of
Number
rate
time
Person
´
=
-
n
10
period
time
the
of
beginning
at the
risk
at
population
period
short time
a
during
occuring
cases
new
Rate
Attack
´
=
n
10
cases)
(primary
period)
time
the
of
beginning
at
n
(populatio
period
short time
a
during
cases
primary
of
contacts
among
cases
new
Rate
Attack
Secondary
´
-
=
n
10
in time
point
a
at
population
study
Total
in time
point
a
at
event
or
disease
the
of
cases
existing
and
New
proportion
Prevalence
´
=
Expected
Observed
SMR
=
n
years
and
10
age
of
years
64
-
15
between
Population
65
15
Population
Ratio
Dependency
´
³
<
=
000
,
1
occurred
births
which
from
Population
period
time
specified
a
during
population
a
in
births
live
of
Number
Rate
Birth
´
=
000
,
1
years
44
-
15
ages
women
of
Population
period
time
specified
a
during
population
a
in
births
live
of
Number
Rate
Fertility
´
=
100
in time
point
same
at the
age
ve
reproducti
of
women
of
Number
in time
point
a
at
method
ive
contracept
a
using)
is
partner
(or whose
using
are
who
pregnancy
of
risk
at
age
ve
reproducti
of
women
of
Number
Prevalence
ive
Contracept
´
=
n
10
occurred
death
which
from
Population
period
given time
a
during
occuring
Deaths
Rate
Mortality
Crude
´
=
00
,
100
occurred
death
which
from
Population
period
given time
a
during
occuring
cause
specific
a
from
deaths
of
Number
Rate
Mortality
Specific
-
Cause
´
=
000
,
1
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
year
1
-
0
ages
infants
among
deaths
of
Number
Rate
Mortality
Infant
´
=
000
,
1
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
days
28
than
less
infants
among
deaths
of
Number
rate
Mortality
Neonatal
´
=
000
,
1
year
same
in the
births
live
of
Number
age
of
year
1
and
age
of
days
28
between
deaths
infant
of
Number
rate
Mortality
al
Postneonat
´
=
000
,
1
deaths
fetal
plus
births
live
of
Number
gestation
weeks
20
least
at
after
deaths
fetal
of
Number
Rate
Death
Fetal
´
=
000
,
1
period
time
same
the
during
44
-
15
ages
women
of
Number
period
time
specified
a
during
done
abortions
of
Number
Rate
Abortion
´
=
000
,
100
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
childbirth
to
due
deaths
of
Number
Rate
Mortality
Maternal
´
=
100
period
time
same
in the
deaths
of
Number
period
time
specified
a
during
cause
specific
a
from
deaths
of
Number
(PMR)
Ratio
Mortality
ate
Proportion
´
=
n
10
period
time
same
the
during
disease
the
of
cases
of
Number
period
time
specified
a
during
disease
specific
a
from
deaths
of
Number
Rate
Fatality
Case
´
=
Years of Potential Life Lost (YPLL) = ∑ (end point – age at death before end point)
For grouped data,
YPLL = ∑for all age groups (# of deaths in each age group) x (endpoint-midpoint of the age group)
Midpoint = age group’s youngest age in years + oldest age +1
2
n
10
point
end
selected
the
below
population
in the
Number
YPLL
Rate
YPLL
´
=
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Page 2 of 3
n
10
occurred
death
which
from
Population
period
given time
a
during
occuring
Deaths
Rate
Mortality
Crude
´
=
n
10
period
time
same
the
during
risk
at
Population
period
given time
a
during
occuring
cases
New
Rate
Incidence
´
=
n
10
persons
all
for
totalled
observed;
person
each
Time
period
n
observatio
during
cases
of
Number
rate
time
Person
´
=
-
n
10
period
time
the
of
beginning
at the
risk
at
population
period
short time
a
during
occuring
cases
new
Rate
Attack
´
=
n
10
cases)
(primary
period)
time
the
of
beginning
at
n
(populatio
period
short time
a
during
cases
primary
of
contacts
among
cases
new
Rate
Attack
Secondary
´
-
=
n
10
in time
point
a
at
population
study
Total
in time
point
a
at
event
or
disease
the
of
cases
existing
and
New
proportion
Prevalence
´
=
Expected
Observed
SMR
=
n
years
and
10
age
of
years
64
-
15
between
Population
65
15
Population
Ratio
Dependency
´
³
<
=
000
,
1
occurred
births
which
from
Population
period
time
specified
a
during
population
a
in
births
live
of
Number
Rate
Birth
´
=
000
,
1
years
44
-
15
ages
women
of
Population
period
time
specified
a
during
population
a
in
births
live
of
Number
Rate
Fertility
´
=
100
in time
point
same
at the
age
ve
reproducti
of
women
of
Number
in time
point
a
at
method
ive
contracept
a
using)
is
partner
(or whose
using
are
who
pregnancy
of
risk
at
age
ve
reproducti
of
women
of
Number
Prevalence
ive
Contracept
´
=
00
,
100
occurred
death
which
from
Population
period
given time
a
during
occuring
cause
specific
a
from
deaths
of
Number
Rate
Mortality
Specific
-
Cause
´
=
000
,
1
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
year
1
-
0
ages
infants
among
deaths
of
Number
Rate
Mortality
Infant
´
=
000
,
1
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
days
28
than
less
infants
among
deaths
of
Number
rate
Mortality
Neonatal
´
=
000
,
1
year
same
in the
births
live
of
Number
age
of
year
1
and
age
of
days
28
between
deaths
infant
of
Number
rate
Mortality
al
Postneonat
´
=
000
,
1
deaths
fetal
plus
births
live
of
Number
gestation
weeks
20
least
at
after
deaths
fetal
of
Number
Rate
Death
Fetal
´
=
000
,
1
period
time
same
the
during
44
-
15
ages
women
of
Number
period
time
specified
a
during
done
abortions
of
Number
Rate
Abortion
´
=
000
,
100
period
time
same
in the
births
live
of
Number
period
time
specified
a
during
childbirth
to
due
deaths
of
Number
Rate
Mortality
Maternal
´
=
100
period
time
same
in the
deaths
of
Number
period
time
specified
a
during
cause
specific
a
from
deaths
of
Number
(PMR)
Ratio
Mortality
ate
Proportion
´
=
n
10
period
time
same
the
during
disease
the
of
cases
of
Number
period
time
specified
a
during
disease
specific
a
from
deaths
of
Number
Rate
Fatality
Case
´
=
n
10
point
end
selected
the
below
population
in the
Number
YPLL
Rate
YPLL
´
=
