Seasonal Patterns
Understanding Seasonality in MMM
Seasonality refers to regular, predictable variations in your KPI that occur at specific times. Decomposition helps isolate and quantify these seasonal effects.
Purpose: Identify seasonal patterns, quantify their impact, and align marketing strategies with natural demand cycles.
Types of Seasonality
Annual Seasonality
Yearly Patterns:
- Holiday periods (Q4 for retail) 
- Summer vacation season 
- Back-to-school period 
- Tax season (for financial services) 
In Decomposition:
- If you have a "Seasonality" group, shows these patterns directly 
- Or visible in total KPI (black line) as regular annual rhythms 
Quarterly Seasonality
Business Cycles:
- End-of-quarter budget spending (B2B) 
- Fiscal year patterns 
- Seasonal product demand 
Example:
Q1: Baseline performance
Q2: 10% above baseline
Q3: 5% above baseline
Q4: 25% above baseline (holiday season)Monthly Seasonality
Within-Year Patterns:
- Payday cycles 
- Month-end effects 
- Specific holiday months 
Weekly Seasonality
Within-Month Patterns:
- Weekend vs. weekday 
- End-of-week patterns 
- Specific day-of-week effects 
Finding Seasonality in Decomposition
Explicit Seasonality Group
If You've Grouped Seasonal Variables:
Look for "Seasonality" group contribution:
January Seasonality: $10,000
July Seasonality: $5,000
December Seasonality: $40,000
Pattern: Strong December peak, moderate January, low summerWhat's Included:
- Holiday indicator variables 
- Monthly dummy variables 
- Seasonal indices 
- Weather effects 
Implicit Seasonality
In Base Group or Overall KPI:
View the black line (Actual) in main chart:
- Regular up-and-down patterns 
- Peaks at same times each year 
- Predictable cycles 
Example - Retail:
Every year:
- January: Post-holiday dip
- Spring (Apr-May): Moderate
- Summer (Jun-Aug): Low season
- Fall (Sep-Nov): Building
- December: Peak (holiday)Quantifying Seasonal Impact
Seasonal Lift Calculation
Compare Peak to Baseline:
December (Peak):
Seasonality Contribution: $50,000
Base Contribution: $100,000
Total: $150,000
Average Month:
Seasonality Contribution: $10,000
Base Contribution: $100,000
Total: $110,000
Seasonal Lift: $50,000 - $10,000 = $40,000
Percentage Lift: 36% above average monthSeasonal Index
Normalize Each Period:
Average Monthly KPI: $500,000
January Index: $400,000 / $500,000 = 0.80 (20% below average)
December Index: $700,000 / $500,000 = 1.40 (40% above average)
Use: Budget allocation, forecastingMarketing Strategy by Season
Peak Season Strategy
High Natural Demand Period:
Characteristics:
- Higher absolute sales 
- Strong seasonality contribution 
- Competitive advertising 
Marketing Approach:
Maintain Presence:
Don't go dark during peak demand
Capture your fair share
Defend against competitorsBut Don't Over-Invest:
Marketing ROI may be lower (crowded market)
Focus on efficiency
Natural demand is already highExample - Holiday Retail (Q4):
Seasonality drives: +$200,000
Marketing contribution: +$150,000 (lower ROI than off-season)
Total lift: $350,000
Strategy: Moderate marketing, let seasonality work for youOff-Season Strategy
Low Natural Demand Period:
Characteristics:
- Lower baseline sales 
- Negative or minimal seasonality contribution 
- Less competitive advertising 
Marketing Approach:
Strategic Investment:
Marketing can have higher incremental impact
Less competition for attention
Opportunity to build brand
Smooth demand cycleExample - Summer for Winter Products:
Seasonality effect: -$50,000 (negative)
Marketing contribution: +$100,000 (higher ROI)
Net: +$50,000
Strategy: Invest to counteract seasonality, build off-season demandShoulder Seasons
Transition Periods:
Build Momentum:
- Ramp up before peak season 
- Capture early demand 
- Pre-season promotions 
Extend Season:
- Keep demand going after peak 
- Capture late buyers 
- Clear inventory 
Seasonal Budget Allocation
Traditional Approach (Follow Seasonality)
Allocate Budget to Match Demand:
Q1: 20% of annual budget (baseline)
Q2: 25% of annual budget (spring increase)
Q3: 20% of annual budget (summer dip)
Q4: 35% of annual budget (holiday peak)Pros: Maximize absolute sales, capitalize on demand Cons: Higher costs in Q4, competitive market
Counter-Seasonal Approach
Invest More in Off-Season:
Q1: 30% of budget (build demand)
Q2: 25% of budget (maintain)
Q3: 30% of budget (combat summer dip)
Q4: 15% of budget (ride natural demand)Pros: Better ROI, less competition, smooth demand Cons: Lower absolute sales, fight natural patterns
Balanced Approach (Recommended)
Combine Both Strategies:
High Season (Q4): 
- 30-40% of budget
- Maintain presence
- Don't over-invest
Shoulder Seasons (Q2, Q3):
- 25-30% of budget
- Build momentum
- Capture opportunity
Low Season (Q1):
- 20-25% of budget
- Strategic investment
- Efficiency focusSeasonal Marketing Insights
Campaign Timing
Align with Seasonality:
Launch Before Peak:
Holiday season peaks in December
Launch campaigns in November
Build awareness before purchase intent peaksExtend Seasons:
Back-to-school traditionally August
Start promotions in July
Extend through SeptemberChannel Mix by Season
Different Channels Perform Differently by Season:
Example:
Summer (Low Season):
- TV less effective (people outdoors)
- Digital more efficient (targeted)
- Strategy: Shift to digital
Winter (High Season):
- TV more effective (people home)
- All channels competitive
- Strategy: Balanced mixPromotional Timing
Leverage or Counter Seasonality:
With Seasonality:
Holiday promotions when demand is naturally high
Amplify natural demand
Example: Black Friday, Christmas salesAgainst Seasonality:
Summer sales to combat low season
Create artificial demand peaks
Example: Summer clearance eventsYear-Over-Year Seasonal Comparison
Track How Seasonality Changes:
December 2023:
Seasonality Contribution: $180,000
December 2024:
Seasonality Contribution: $210,000
Change: +17% seasonal effect
Insight: Holiday season getting stronger
Action: Plan for continued growthHelps Identify:
- Strengthening seasonal patterns 
- Weakening effects 
- Structural market changes 
- Consumer behavior shifts 
Forecasting with Seasonal Patterns
Use Historical Patterns to Predict:
Step 1: Calculate Seasonal Indices
Each month's index = Month Average / Overall AverageStep 2: Apply to Forecast
Base forecast: $500,000/month
January index: 0.80
January forecast: $500,000 × 0.80 = $400,000Step 3: Add Marketing Plans
Planned marketing contribution: +$100,000
Total January forecast: $500,000Seasonal Analysis Checklist
Identify Patterns:
- [ ] Clear seasonal group in decomposition? 
- [ ] Regular patterns in total KPI? 
- [ ] Same peaks each year? 
Quantify Impact:
- [ ] Peak vs. baseline difference? 
- [ ] Seasonal lift percentage? 
- [ ] Contribution by period? 
Strategic Decisions:
- [ ] Budget allocation by season? 
- [ ] Campaign timing optimized? 
- [ ] Channel mix adjusted seasonally? 
Year-Over-Year:
- [ ] Seasonal patterns strengthening? 
- [ ] New patterns emerging? 
- [ ] Historical trends continuing? 
Common Seasonal Patterns by Industry
Retail:
- Q4 peak (holidays) 
- January dip (post-holiday) 
- Back-to-school (Aug-Sep) 
Travel:
- Summer peak (Jun-Aug) 
- Holiday periods (Thanksgiving, Christmas) 
- Spring break (March) 
Financial Services:
- Tax season (Jan-Apr) 
- Year-end (Dec) 
- Quarterly patterns 
B2B:
- End-of-quarter budget spend 
- Fiscal year-end 
- Trade show seasons 
E-Commerce:
- Cyber Week (Nov-Dec) 
- Prime Day (July) 
- Monthly payday patterns 
Summary
Key Takeaways:
Seasonality Shows:
- Predictable demand patterns 
- Natural business cycles 
- Market rhythms 
Use Seasonality To:
- Time campaigns effectively 
- Allocate budgets wisely 
- Forecast accurately 
- Plan inventory and resources 
Strategic Approaches:
- Follow seasonality (maximize peaks) 
- Counter seasonality (smooth demand) 
- Balance both (optimal approach) 
Best Practices:
- Track year-over-year changes 
- Adjust marketing by season 
- Plan 12 months ahead 
- Don't fight strong seasonality 
Next Steps:
- Identify your seasonal patterns 
- Quantify seasonal impact 
- Develop season-specific strategies 
- Monitor and adjust over time 
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