During a PPSM event, a team's 5 Whys analysis terminates at 'insufficient
training.' Which critique best reflects a root-cause analysis error?
A. The analysis stopped at a symptom rather than a systemic cause.
B. The team failed to use a Fishbone diagram first.
C. The 5 Whys should always produce exactly five levels.
D. Training deficiencies are never root causes.
Correct Answer: A - The analysis stopped at a symptom rather
than a systemic cause.
RATIONALE
Stopping at 'insufficient training' is a classic error because it names a
symptom/contributing factor, not the systemic reason training was
insufficient (e.g., no needs assessment, no standard). B is wrong
because Fishbone is optional, not prerequisite. C is a misconception-5
Whys is not rigidly five. D is false; training gaps can be root causes if
systemic, but here the analysis is too shallow.
Question 2
A Pareto chart shows that 3 of 12 defect categories account for 78% of total
defects. A manager proposes addressing all 12 categories simultaneously. What
is the most defensible Lean response?
A. Agree; comprehensive action prevents recurrence.
B. Focus first on the vital few to maximize impact with limited resources.
C. Reject Pareto; it oversimplifies multivariate causation.
D. Address the 9 trivial many first to clear noise.
Correct Answer: B - Focus first on the vital few to maximize
impact with limited resources.
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, RATIONALE
Pareto principle directs prioritization of the vital few (the 3 categories
causing 78%) to achieve the greatest improvement with constrained
resources. A spreads resources too thin. C dismisses a valid
prioritization tool. D inverts the principle and wastes effort on
low-impact categories.
Question 3
In a Value Stream Map, a process has 4 steps with cycle times 2, 4, 3, and 5
minutes and no inventory between steps. What is the value-added time and the
lead time?
A. Value-added = 5 min; lead time = 14 min
B. Value-added = 14 min; lead time = 14 min
C. Value-added = 0 min; lead time = 14 min
D. Value-added = 5 min; lead time = 5 min
Correct Answer: B - Value-added = 14 min; lead time = 14 min
RATIONALE
With no inventory or waiting, lead time equals sum of cycle times
(2+4+3+5=14 min). All steps are assumed value-added here because
no non-value-added activities are specified. A incorrectly equates
value-added with the longest step. C assumes no value-added, which is
unsupported. D confuses lead time with a single step.
Question 4
Which scenario best exemplifies the Lean waste of 'overprocessing' rather than
'defects'?
A. A unit re-enters data into three separate systems that do not share
fields.
B. A product is assembled with a missing fastener and must be reworked.
C. Operators wait for a supervisor's approval before each step.
D. Excess inventory of raw materials occupies floor space.
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, Correct Answer: A - A unit re-enters data into three separate
systems that do not share fields.
RATIONALE
Overprocessing is doing more work than the customer values, such as
redundant data entry across systems. B is a defect (rework). C is
waiting. D is inventory waste.
Question 5
A 6S audit reveals that tools are often missing and searches consume 15
minutes per shift. Which 6S pillar most directly addresses this?
A. Seiri (Sort)
B. Seiton (Set in order)
C. Seiso (Shine)
D. Shitsuke (Sustain)
Correct Answer: B - Seiton (Set in order)
RATIONALE
Seiton (Set in order) establishes designated locations and visual
controls so tools are findable, directly reducing search time. Seiri
removes unneeded items. Seiso is cleaning. Shitsuke is sustaining
discipline, which supports but does not directly organize locations.
Question 6
A Fishbone diagram lists 'material,' 'machine,' 'method,' and 'manpower' as
main branches. A team adds 'measurement' and 'environment.' What is the
primary benefit of this expansion?
A. It ensures the diagram has exactly six branches.
B. It broadens the search for potential causes beyond the original four
categories.
C. It eliminates the need for a 5 Whys analysis.
D. It guarantees identification of the true root cause.
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