Interviewer view · keep this screen to yourself
Standard: Cutting waiting times at a government service center
You run the case. Read the prompt, answer questions from the notes below, and share data only when the candidate asks for it or gets stuck. Score at the end.
Case timer
00:00
1. Read the prompt aloud
Read it slowly, then pause. Let the candidate ask questions before they structure.
A Saudi government agency wants to cut the average wait at its main service center from about 90 minutes to under 30 minutes, without a big rise in running costs. How would you approach this?
Format note: Difficulty: Standard. Format: candidate-led, with interviewer dialogue. Industry: Public sector. Region: Saudi Arabia. Interview length: about 30 minutes. The company is fictional and all figures are illustrative.
2. Answers to clarifying questions
Give these answers only if the candidate asks. If they ask something not listed, give a sensible answer or say it does not matter here.
If asked: Is the 90-minute wait an average across the day?
Answer: Yes, an average.
If asked: How many visitors come, and how long does a visit take at the counter?
Answer: About 480 visitors in an 8-hour day; about 15 minutes per visit, with 15 counters open.
If asked: Are there limits?
Answer: The agency prefers not to add permanent staff; a digital channel would cost about SAR 2 million one time.
3. The hypothesis a strong candidate states
Listen for an early, testable guess like this one. It does not need to match word for word.
If the counters are almost always busy, even small changes in arrivals create long queues. My hypothesis is that the center runs close to full capacity, and the best lever is fewer avoidable visits rather than more counters.
4. A model structure
Compare the candidate's structure with this one. A different split can be just as good if it is clean and fits the problem.
- Wait depends on arrivals and capacity
- Key: Arrivals per hour, and how many are avoidable
- Service capacity (counters x visits per hour)
- Utilization and the queue (Little's Law)
- Levers: fewer avoidable visits, online services, more counters
5. The working, step by step
Each step shows how a strong candidate works it out. Share a new fact from it only when the candidate asks or is stuck, and let them do the math: the result in the dark box is what they should reach.
Step 1: Arrivals per hour
What a strong candidate does: Candidate: "480 visitors over 8 hours is:"
Arrivals per hour: 480 ÷ 8 = 60
Step 2: Capacity per hour
What a strong candidate does: Candidate: "Each counter serves 4 visitors an hour at 15 minutes each, so 15 counters serve:"
Visitors served per hour: 15 × 60 ÷ 15 = 60
Step 3: Utilization
What a strong candidate does: Candidate: "Arrivals equal capacity, so counters are busy all the time. At 100 percent a queue is unstable: any delay builds it up, and at peaks it only clears after closing."
Utilization (%): (480 ÷ 8) ÷ (15 × 60 ÷ 15) × 100 = 100
Step 4: People waiting
What a strong candidate does: Candidate: "By Little's Law, people waiting equals arrivals per hour times the wait in hours."
Average number waiting: 60 × 1.5 = 90
Step 5: Counters needed at 80 percent utilization
What a strong candidate does: Candidate: "Queues stay short when counters are busy about 80 percent of the time or less."
Counters needed: 60 × 15 ÷ 60 ÷ 0.8 = 18.75
Step 6: Cost of adding counters
What a strong candidate does: Interviewer: "Each extra counter costs about SAR 300,000 a year in staff." Four more counters would cost:
Yearly cost (SAR): (19 - 15) × 300,000 = 1,200,000
Step 7: Curveball: avoidable visits
What a strong candidate does: Interviewer: "One more fact: about 20 percent of visits are repeat visits, because applicants forgot a document the first time." Candidate: "Then fixing that alone cuts arrivals to:"
Arrivals per hour without repeat visits: 60 × (1 - 0.2) = 48
Step 8: Adding online services
What a strong candidate does: Candidate: "If 30 percent of the remaining visits move online, utilization of today's 15 counters becomes:"
Utilization after both changes (%): 60 × (1 - 0.2) × (1 - 0.3) ÷ 60 × 100 = 56
The recommendation to listen for
At the end, say: "The CEO walks in. What is your recommendation?"
Cut avoidable visits first, then move simple services online, rather than adding counters. First, the center runs at 100 percent utilization, which is why about 90 people are waiting on average. Second, a document checklist sent before the visit, plus an online pre-check, targets the 20 percent of repeat visits at very low cost; the 56 percent figure that follows assumes it removes nearly all of them. Third, moving 30 percent of simple services online for about SAR 2 million one time brings utilization to about 56 percent with today's 15 counters, well below the 80 percent level where queues stay short; at 80 percent or lower with 15 counters, the average wait should fall to a few minutes, well under the 30-minute goal. Four extra counters, by contrast, would cost SAR 1.2 million every year. Track average wait, first-visit resolution, and the share of services completed online each week.
Risks a strong answer names: Some citizens may prefer or need in-person service; Online services need good design, or they create new calls and visits.
Next steps: Launch a document checklist by text message before appointments; Pick the five simplest services to move online first.
Strong versus weak
A strong answer
Used utilization and Little's Law to explain the queue, found the avoidable demand through a good question, and compared one-time and yearly costs.
A weak answer
Recommended hiring more staff straight away, missing the repeat visits and the cheaper online option.
Score the candidate
Score each criterion from 1 to 5. A 2 or a 4 sits between the descriptions.
This case has no exhibit. Score Exhibit reading on how the candidate used the data you gave them: did they pick out the number that matters and say what it means?
Total
0 out of 25
Score all five criteria to see the band and the feedback template.