10 Lottery Event Failure Cases and Countermeasures
"We received complaints about unfairness in the lottery..."
"System troubles ruined the entire event..."
"Participants left dissatisfied..."
When preparation or management methods are flawed, lottery events can lead to major troubles.
In this article, we'll learn from actual failure cases and explain countermeasures to avoid repeating the same mistakes.

Failure Case 1: Complaints Due to Opaque Lottery Method
What Happened
Situation:
A prize lottery was held at a company's year-end party. The organizer determined winners using Excel's random number function, but participants voiced doubts: "Is it really random?"
Complaint Details:
- "It seems like the organizer's friends keep winning"
- "Can't the formulas be manipulated?"
- "We can't trust the process because we can't see it"
Results:
- Some people declined their prizes
- Trust in the organizer decreased
- Participation rate in the next year-end party declined
Root Cause Analysis
Root Causes:
Process Opacity
- The lottery mechanism is invisible
- Participants are passive
- Black box operation
Lack of Advance Explanation
- No explanation of the lottery method
- No evidence of fairness provided
Absence of Records
- Unclear who conducted the lottery and when
- Results cannot be verified
Countermeasures
Immediate Response:
- Change lottery method (from next time)
- Apologize and explain to participants
- Collect feedback
Permanent Countermeasures:
Adopt Transparent Lottery Methods
- All participants involved in the process
- Utilize Online Amidakuji
- A system everyone can accept
Thorough Advance Explanation
- Announce lottery method in advance
- Explain the basis for fairness
- Provide time for questions
Preserve Records
- Screenshot the lottery process
- Record date/time and participants
- Enable later verification
Failure Case 2: Backlash from Incorrect Probability Explanation
What Happened
Situation:
An SNS campaign advertised "Gifts for everyone!" but in reality, only 10 people won through a lottery. Participants caused a backlash on social media claiming "It's a scam."
Complaint Details:
- "We thought everyone would receive one"
- "The expression is misleading"
- "This company can't be trusted"
Results:
- Significant decline in corporate image
- Social media backlash
- Flood of inquiries to customer support
- Costs for apology and additional prize distribution
Root Cause Analysis
Root Causes:
Ambiguous Announcement
- The meaning of "everyone" is unclear
- Lottery nature not clearly stated
Lack of Confirmation
- No legal review before announcement
- No review by multiple people
Insufficient Understanding of Prize Labeling Act
Countermeasures
Immediate Response:
- Issue official apology
- Distribute additional prizes
- Correct the explanation
Permanent Countermeasures:
- Clarify Announcements
× "Gifts for everyone!"
○ "Gifts for 10 winners selected by lottery!"
○ "Winners selected by lottery from applicants"
- Specify Win Probability
Example: "With 100 applicants, win probability is 10%"
- Implement Legal Review
- Lawyer confirmation before announcement
- Compliance with Prize Labeling Act
- Thorough risk management
Failure Case 3: Lottery Interrupted by System Trouble
What Happened
Situation:
A lottery was scheduled to be held on Zoom during an online seminar with 300 participants. However, the lottery tool malfunctioned, interrupting the event for 30 minutes.
Impact:
- Participant dropout (over 100 people)
- Significant schedule delay
- Shortened lecture time
- Complaints generated
Root Cause Analysis
Root Causes:
Insufficient Pre-testing
- No testing in production environment
- No operation verification with large numbers
Lack of Backup Plan
- No alternative methods prepared
- No manual lottery method decided
Tool Selection Mistake
- Tool not compatible with large numbers
- Insufficient consideration of communication environment
Countermeasures
Immediate Response:
- Switch to alternative lottery method
- Explain and apologize to participants
- Extend or reschedule
Permanent Countermeasures:
- Thorough Pre-testing
Test Checklist:
□ Test in production-equivalent environment
□ Operation verification with expected participant count
□ Communication speed verification
□ Multi-browser operation verification
□ Smartphone participation test
- Prepare Backup Plan
Plan A: Online lottery tool
Plan B: Excel random numbers (screen sharing)
Plan C: Paper lottery (pre-prepared)
- Select Reliable Tools
- Track record with large numbers
- Not dependent on communication environment
- Simple operation
Failure Case 4: Duplicate Wins Cause Trouble
What Happened
Situation:
In a paper lottery, there were two tickets with the same number, resulting in two people winning the same prize. This was discovered later, causing trouble.
Complaint Details:
- "Which one is the real winner?"
- "The management is sloppy"
- "We should do it over again"
Results:
- Cost of providing two prizes
- Decreased event credibility
- Damaged organizer reputation
Root Cause Analysis
Root Causes:
Preparation Stage Mistakes
- Insufficient verification when creating tickets
- No double-checking
No Guarantee of 1-to-1 Correspondence
Countermeasures
Immediate Response:
- Provide prizes to both parties
- Apologize to all participants
- Explain cause and recurrence prevention measures
Permanent Countermeasures:
Adopt Methods with Guaranteed 1-to-1 Correspondence
- Amidakuji (mathematically guaranteed)
- Digital tools
Checks When Using Paper Lottery
□ Verify numbers when creating
□ Have another person double-check
□ Confirm total count before drawing
□ Put drawn tickets in separate box
Failure Case 5: Too Many Participants, Time Overrun
What Happened
Situation:
At a company event with 500 people, everyone drew paper tickets in order. It took 2 hours, significantly delaying the entire event.
Impact:
- Other programs shortened or cancelled
- Participant fatigue and stress
- Venue fee overrun
Root Cause Analysis
Root Causes:
Participant Size Estimation Error
- 500 people × 30 seconds each = 250 minutes needed
- Insufficient advance simulation
Wrong Method Selection
- Method unsuitable for large numbers
- Non-scalable design
Countermeasures
Immediate Response:
- Change to representatives-only lottery
- Time-saving innovations
Permanent Countermeasures:
Select Large-Group Compatible Methods
- Online lottery (participate in advance)
- Lottery drum (efficient)
- Digital tools
Advance Simulation
Time Required = Participant Count × Time per Person × 1.2 (buffer)
- Distributed Processing
- Participate online in advance
- Only announce results on the day
Failure Case 6: Handling Absentees Incorrectly
What Happened
Situation:
In a pre-participation lottery, an absent person won. Unable to contact them and refusing proxy receipt caused trouble.
Complaint Details:
- "It's unfair that I won but can't receive it"
- "There was no advance explanation"
Root Cause Analysis
Root Causes:
Unclear Rules
- No pre-determined handling of absentees
- Insufficient explanation to participants
Lack of Flexibility
- Unable to respond flexibly
- Rigid management
Countermeasures
Advance Measures:
- Clarify and Communicate Rules
"Handling Absentees"
□ Win void if absent
□ Proxy receipt allowed
□ Mail later
□ Carry over to next time
Advance Confirmation
- Confirm attendance plans
- Contact information in case of absence
Flexible Response
- Judge according to situation
- Prioritize participant satisfaction
Failure Case 7: No Record of Results, Unable to Handle Complaints
What Happened
Situation:
After the lottery, there was a complaint: "I won but my name wasn't called." However, with no records, verification was impossible.
Impact:
- Prolonged complaint handling
- Breakdown of trust
- "He said, she said" trouble
Root Cause Analysis
Root Causes:
Lack of Records
- Results not documented
- No photos or screenshots
Unverifiable Situation
- No evidence
- Third parties cannot confirm
Countermeasures
- Thorough Record-keeping
Required Records:
□ Lottery date and time
□ Lottery method
□ Winner list
□ Process screenshots
□ Witness signatures (for important cases)
Utilize Digital Tools
Multi-person Verification
- Assign witnesses
- Double-check
Failure Case 8: Personal Information Leak
What Happened
Situation:
Email addresses of lottery participants were mistakenly sent to everyone, leaking personal information.
Impact:
- Personal Information Protection Act violation
- Loss of credibility
- Legal liability
- Reporting obligation triggered
Root Cause Analysis
Root Causes:
Operational Error
- Used TO/CC instead of BCC
- Lack of confirmation
Lax Personal Information Management
- No handling rules established
- Insufficient training
Countermeasures
- Pre-send Confirmation
□ Are recipients in BCC?
□ Are attachments correct?
□ Is personal information included?
□ Another person double-checks
Methods Not Requiring Personal Information
- Lottery without email addresses
- Participation with nicknames
- Ensure anonymity
Security Measures
- Encrypted communication
- Access restrictions
- Log recording
Failure Case 9: Unequal Prize Values Cause Dissatisfaction
What Happened
Situation:
1st place prize was ¥100,000, 2nd place and below were ¥500. The massive gap caused complaints from 2nd place winners and below.
Complaint Details:
- "The gap is too large"
- "At least a few thousand yen value would be nice"
- "I feel ridiculed"
Root Cause Analysis
Root Causes:
Prize Design Mistake
- Gap is too large
- Lack of consideration for participant psychology
Skewed Budget Allocation
- Budget concentrated on 1st place
- Lack of consideration for majority
Countermeasures
- Balance Prize Values
Bad Example:
1st place: ¥100,000
2nd place and below: ¥500
Good Example:
1st place: ¥30,000
2nd-5th place: ¥5,000
6th-20th place: ¥2,000
"No Losers" Design
- Participation prize for everyone
- Tiered prize structure
- Increase win probability
Enhanced Participation Prizes
- Something nice even without winning
- Company original goods
Failure Case 10: Ambiguous Eligibility Causes Trouble
What Happened
Situation:
It was an "employees only" lottery, but temporary staff and part-timers also participated. Later it was revealed to be "full-time employees only," and some wins were cancelled.
Complaint Details:
- "You should have explained from the beginning"
- "It's terrible to raise hopes and then cancel"
- "This is discrimination"
Root Cause Analysis
Root Causes:
Unclear Eligibility
- Ambiguous definition of "employee"
- Insufficient advance notice
Lack of Verification
- No eligibility verification at participation
- No participant list checking
Countermeasures
- Clarify Eligibility
× "Employees only"
○ "Full-time employees only (excluding contract and temporary staff)"
○ "All staff (regardless of employment type)"
Advance Confirmation
- Verify eligibility at participation
- Automatic system determination
- Confirm in advance for questionable cases
Ensure Fairness
- Make target as broad as possible
- Be careful not to discriminate
Trouble Prevention Checklist
Planning Stage
Announcement Stage
Implementation Stage
Post-event Response
Summary
To prevent lottery event failures:
Ensure Transparency:
Thorough Preparation:
- Pre-testing
- Backup plan
- Rehearsal
Preserve Records:
- Record results
- Screenshot process
- Enable verification
Legal Compliance:
Consideration for Participants:
- Fair prize design
- Clear rules
- Courteous explanation
Learn from failures and make your next event even better!