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CHAPTER
13
Breakeven Analysis
13.1 BREAKEVEN ANALYSIS FOR A SINGLE PROJECT
When one
of
the engineering economy
symbols-P,
F, A,
i,
or
n-is
not known
or not estimated, a breakeven quantity can be determined by setting an equiva-
lence relation for
PW
or
AW
equal to zero. This form
of
breakeven analysis has
been used many times so far. For example, we have solved for the rate
of
return
i*, found the payback period nfl' and determined the P, F, A, or salvage value S
at which a series
of
cash flow estimates return a specific MARR. Methods used
to determine the quantity are
Direct solution by hand
if
only one factor is present (say, P / A)
or
only single
amounts are estimated (for example,
P and
F)
.
Trial and error by hand when multiple factors are present.
Computer spreadsheet when cash flow and other estimates are entered into
spreadsheet cells and used in resident functions, such as
PV,
FV,
RATE,
IRR,
NPV, PMT, and NPER.
We
now concentrate on the determination
of
the breakeven quantity
for
a
decision variable. For example, the variable may be a design element to mini-
mize cost, or the production level needed to realize revenues that exceed costs by
10
%.
This quantity, called the breakeven point
QB
E'
is determined using relations
for revenue and cost at different values
of
the variable
Q.
The size
of
Q may be
expressed
in
units per year, percentage
of
capacity, hours per month, and many
other dimensions.
Figure
13-1a
presents different shapes
of
a revenue relation identified as
R.
A linear revenue relation
is
commonly assumed, but a nonlinear relation
is
often
more realistic. It can model an increasing per unit revenue with larger volumes
(curve J
in
Figure
13-la)
, or a decreasing per unit price that usually prevails at
higher quantities (curve 2).
Costs, which may be linear or nonlinear, usually include two
components-
fixed and
variable-as
indicated in Figure 13-1b.
Fixed costs (FC). Includes costs such as buildings, insurance, fixed over-
head, some minimum level
of
labor, equipment capital recovery, and infor-
mation systems.
Variable costs
(Ve).
Includes costs such as direct labor, materials, indirect
costs, contractors, marketing, advertisement, and warranty.
The fixed cost component is essentially constant for all values
of
the variable, so it
does not vary for a large range
of
operating parameters, such as production level
or workforce size. Even
if
no units are produced, fixed costs are incurred at some
threshold level.
Of
course, this situation cannot last long before the plant must
shut down to reduce fixed costs. Fixed costs are reduced through improved
equipment, information systems and workforce utilization, less costly fringe ben-
efit packages, subcontracting specific functions, and so on.
Variable costs change with production level, workforce size, and other parame-
ters. It is usually possible to decrease variable costs through better product design,
manufacturing efficiency, improved quality and safety, and higher sales volume.