Certified Six Sigma Black Belt Exam Voice of the Customer (VOC) 4 — Questions and Answers
Question 1: Which of the following best distinguishes 'stated needs' from 'latent needs' in VOC collection?
- Stated needs are internal; latent needs are external
- Stated needs are explicitly expressed by customers; latent needs are unarticulated but impactful when met (Correct answer)
- Stated needs are measurable; latent needs cannot be quantified
- Stated needs come from surveys; latent needs come from complaints
Correct answer: Stated needs are explicitly expressed by customers; latent needs are unarticulated but impactful when met
Latent (unstated) needs are desires customers have not consciously identified; discovering them through observation creates competitive advantage.
Question 2: A project team segments customers by usage frequency and finds that heavy users have completely different CTQs than light users. What is the best course of action?
- Average the CTQs across both segments for simplicity
- Develop separate CTQs or specifications for each segment (Correct answer)
- Eliminate light users from the VOC analysis
- Ignore the difference and focus on internal process capability
Correct answer: Develop separate CTQs or specifications for each segment
Different customer segments often have distinct critical requirements; a single CTQ set may fail to satisfy any segment optimally.
Question 3: Net Promoter Score (NPS) is calculated as:
- (Promoters + Passives) / Total respondents × 100
- % Promoters − % Detractors (Correct answer)
- % Satisfied − % Dissatisfied
- (Promoters × 10) / Total responses
Correct answer: % Promoters − % Detractors
NPS = percentage of Promoters (score 9–10) minus percentage of Detractors (score 0–6), ignoring Passives (7–8).
Question 4: During a DMAIC Define phase, a team creates a SIPOC diagram. How does SIPOC support VOC?
- SIPOC measures process sigma level before VOC is gathered
- SIPOC identifies the Customer column, clarifying whose voice should be collected (Correct answer)
- SIPOC replaces the need for customer interviews
- SIPOC quantifies CTQ specifications directly
Correct answer: SIPOC identifies the Customer column, clarifying whose voice should be collected
The 'C' in SIPOC explicitly identifies relevant customer groups, ensuring VOC collection targets the right stakeholders.
Question 5: A Black Belt discovers that a key CTQ has a specification limit of ≤ 5 seconds response time, but the current process averages 4.2 seconds with σ = 0.6. What is the process capability index (Cpk) to one decimal?
- 0.4 (Correct answer)
- 0.7
- 1.4
- 2.1
Correct answer: 0.4
Cpk = (USL − mean) / (3σ) = (5 − 4.2) / (3 × 0.6) = 0.8 / 1.8 ≈ 0.44, which rounds to 0.4.
Question 6: When prioritizing CTQs for a Six Sigma project, which tool helps the team decide which requirements have the highest impact on customer satisfaction relative to process difficulty?
- Control chart
- Prioritization matrix (Impact vs. Effort) (Correct answer)
- Scatter plot
- FMEA RPN ranking
Correct answer: Prioritization matrix (Impact vs. Effort)
A prioritization matrix scores CTQs by customer impact and implementation difficulty, focusing resources on high-value, achievable improvements.
Question 7: Which statement about the relationship between VOC and the project charter is most accurate?
- The project charter is written before any VOC is collected
- VOC data informs the problem statement and goal statement in the project charter (Correct answer)
- The project charter replaces the need for formal VOC collection
- VOC is only relevant after the charter is approved
Correct answer: VOC data informs the problem statement and goal statement in the project charter
VOC evidence validates that the problem is customer-driven and guides the measurable goal statement in the charter.
Certified Six Sigma Black Belt Exam Voice of the Customer (VOC) 4
Which of the following best distinguishes 'stated needs' from 'latent needs' in VOC collection?