Page 110 - Six Sigma Advanced Tools for Black Belts and Master Black Belts

OTE/SPH
OTE/SPH
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Current Reality Tree 95
Table 8.2 List of negatives and corresponding whys.
Negatives Whys
N1. Operators cannot cope with the W1. User feels frustrated
number of calls W1a. User waits too long to be served
N2. User wastes time going through all W2. User feels frustrated
the options W2a. User wastes time on non-value-added
waiting
N3. Most of the time still need to talk to W3. Wasted time going through all the other
operator options
W3a. Need to wait a long time for the
operator to attend to the call

Thewhysexplainwhythenegativesarebadinrelationtothegoal.Therecanbemore
than one why for any negative. This is to justify the importance of the negatives. If you
cannot say why a given ‘negative’is bad in relation to the goal of the system, it cannot
be that important. Typically, all whys are UDEs by definition. Write down the whys
to the right of the negatives, naming them in an analogous manner to the negatives,
so that whys W1, W1a, W1b, . . . are associated with N1, and W2, W2a, . . . with N2
(Table 8.2).
The causes are the reasons why the negatives have occurred, and there can be more
than one for any negative. Write these down to the left of the negatives, numbering
them in the same way as the whys (Table 8.3). Notice that the whole table is quite
messy; some whys are the same as the negatives in another row, and some negatives
are actually causes. This is to be expected, as there is no fixed pattern of the cause-
and-effect relationship. This table is just the first brainstorming stage to gather enough

Table 8.3 List of negatives and corresponding whys and causes.

Causes Negatives Whys
C1. Pre-set option not N1. Operators cannot cope W1. User feels frustrated
comprehensive enough with the number of calls W1a. User waits too
C1a. Operators are long to be served.
inexperienced
C1b. Not enough operators
C2. Options are not arranged in N2. User wastes time going W2. User feels frustrated
order of popularity through all the options W2a. User wastes time
C2a. Classifications are not clear on non-value-added
waiting
C3. Users do not want to go N3. Most of the time still W3. Wasted time going
through the options need to talk to operator through all the other
C3a Users do not want to deal options
with a machine W3a. Need to wait a long
C3b. Users cannot get help from time for the operator
the options to attend to the call