Forecast by Design: Decision-Oriented Time Series Analytics in the Age of AI
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Advances in data analytics and artificial intelligence have transformed forecasting by making sophisticated models faster, more accessible, and increasingly automated. However, while generating forecasts has become easier, making sound decisions under uncertainty remains a complex challenge. This book argues that the true value of forecasting lies not in producing predictions alone, but in designing systems that effectively translate imperfect forecasts into informed decisions. It introduces the concept of Forecast-by-Design, which shifts forecasting education from a focus on analytical techniques to a framework that integrates data, models, evaluation, trust, and decision-making within real-world organizational contexts.
The book also emphasizes the development of judgment, critical thinking, and decision capability alongside technical skills. Rather than treating AI as a replacement for human expertise, it presents AI as a learning and reasoning partner that supports analysis while preserving human responsibility and accountability. Through a structured learning approach and AI-supported activities, students progress from understanding forecasting concepts to designing and evaluating decisions under uncertainty. Ultimately, the book prepares learners to use forecasting responsibly by combining quantitative rigor, analytical reasoning, and sound decision design in an AI-enabled world.
Preface
How to Use This Book (For Instructors)
Part I Thinking in Time: The Logic of Forecasting
Chapter 1 The Logic of Time and Decision
Why Forecasting Is a Design Problem, Not a Modeling Task
Opening Story: The Oil Price Rollercoaster
1.1 Why Forecasting Matters in Business and Policy
1.2 Forecasting vs. Prediction: Thinking Through Time vs. Conditions
1.3 The Four Analytical Pillars of Modern Forecasting
1.4 Statistical Learning and Machine Learning: Two Ways to Build Trust
1.5 Structured vs. Unstructured Data: Two Forms of Evidence
1.6 AI and the Expansion of Forecasting Design
1.7 Time as Data: Trend, Seasonality, and Noise
1.8 Uncertainty and the Forecasting Decision Loop
1.9 Forecasting-by-Design
SkillBox 1: Seeing Demand Through Time
LearningLab 1: Thinking Through Time
DesignStudio 1: Designing a Forecast-Informed Decision Process
Mini-Case 1: Government Revenue Forecasting Under Uncertainty
Check Your Learning 1: Reasoning, Interpretation, and Design
Chapter 2 Smoothing Signals for Decision Sensemaking
Designing Fast, Interpretable Signals for Decisions
Opening Story: From Pandemic Curves to Pizza Crowds
2.1 Why Smoothing Supports Decision Sensemaking
2.2 How Smoothing Reveals Temporal Signals
2.3 Flat and Fading Memory: Moving Average and Exponential Smoothing
2.4 Choosing Responsiveness: Designing Memory for Decisions
2.5 Managerial Trade-Offs: Accuracy, Agility, and Trust
SkillBox 2: Smoothing for Direction, Not Prediction
LearningLab 2: Interpreting Smoothed Signals with AI
DesignStudio 2: Designing Directional Signals for Decisions
Mini-Case 2: Acting on Imperfect Signals
Check Your Learning 2: Smoothing for Direction, Not Prediction
Part II Modeling the Future: Foundations & Production
Chapter 3 Seeing Structure in Time
Decomposition as a Tool for Interpretation and Communication
Opening Story: Marriott’s Road Back to Full Occupancy
3.1 Decomposition as a Way of Thinking About Time
3.2 The Core Components of Temporal Structure
3.3 Additive and Multiplicative Structure: How Components Combine
3.4 Decomposition as a Communication Tool
SkillBox 3: Seeing Structure in Real Data
LearningLab 3: Reasoning About Structure with AI
DesignStudio 3: Designing Structure into Decision Systems
Mini-Case 3: Making Sense of Time in a New Context
Check Your Learning 3: Seeing Structure in Time
Chapter 4 Designing Visible Temporal Structure
Forecasting with Trend and Seasonality as Explicit Components
Opening Story: Tokyo Electric Power and the Cost of Misreading Visible Structure 9
4.1 From Seeing Structure to Designing It
4.2 What Explicit-Structure Forecasting Does
4.3 STL as a Representative Explicit-Structure Method
4.4 Additive and Multiplicative Thinking
4.5 The Explicit-Structure Forecasting Workflow
4.6 Business Interpretation: Why Visible Components Matter
4.7 Contrast Learning: Smoothing Vs. Explicit Forecasting
4.8 Boundary of the Chapter: What Visible Structure Cannot Resolve
SkillBox 4: Forecasting with Visible Structure Using STL
LearningLab 4: Reasoning with Explicit Structure
DesignStudio 4: Designing a Planning Response Around Visible Structure
Mini-Case 4: Choosing Whether Visible Structure Is Sufficient
Check Your Learning 4: Visible Temporal Structure in Forecast Design
Chapter 5 Designing Hidden Temporal Structure in Forecasting
Dependence, Memory, and Implicit Time Behavior
Opening Story: Grid Memory at Tokyo Electric Power
5.1 From Visible Structure to Hidden Structure
5.2 Dependence, Memory, and Shock Behavior
5.3 Why Stabilization Comes Before Dependence
5.4 Implicit Structure Through ARIMA/SARIMA
5.5 Comparing Explicit and Implicit Forecasting Design
SkillBox 5: Forecasting with Hidden Structure (ARIMA/SARIMA)
LearningLab 5: Using AI to Reason About Hidden Structure
DesignStudio 5: Designing Forecast Governance When Structure Is Hidden
Mini-Case 5: Choosing How to Handle Hidden Structure
Check Your Learning 5: Invisible Temporal Structure in Forecast Design
Chapter 6 Governing Forecasts Over Time
Forward Validation, Residual Signals, and Forecast Evolution
Opening Story: Airbnb’s Balancing Act—When Forecasts Lose Their Footing
6.1 Why Forecasts Fail Quietly
6.2 Accuracy and Reliability Are Not the Same Question
6.3 Residuals as Signals, Not Just Errors
6.4 Forward Validation—Watching Forecast Behavior as Time Moves Forward
6.5 Forecast Evolution—Maintain, Refit, or Rethink
SkillBox 6: Governing Forecasts Through Residual Signals
LearningLab 6: Using AI to Reason About Forecast Trust
DesignStudio 6: Designing a Forecast Governance Process
Mini-Case 6: When Forecast Trust Erodes
Check Your Learning 6: Governing Forecasts Over Time
Part III Forecasting in the Age of AI
Chapter 7 Forecasting Systems in the Age of AI
Extending Structure with Machine Learning and Generative Reasoning
Opening Story: The Moment Forecasting Changed at Netflix
7.1 From Box–Jenkins to Forecasting Systems in the Age of AI
7.2 Forecasting Systems in the Age of AI
7.3 Hybrid and Generative Forecasting Systems
7.4 Explainability, Bias, and Ethics in AI-Era Forecasting Systems
SkillBox 7: One Dataset, Four Forecasting Systems
LearningLab 7: Interpreting AI-Based Forecasting Systems
DesignStudio 7: Designing a Governed Hybrid Forecasting System
Mini-Case 7: When Forecasts Disagree: Designing Decisions Under AI Uncertainty
Check Your Learning 7: Forecasting Systems in the Age of AI
Part IV Workflow Integration
Chapter 8 Designing Decisions with Forecasts
An End-to-End Forecasting in Action, Accountability, and Uncertainty
(with a Capstone Project Assignment)
Opening Story: Forecasting Public Health Emergencies
8.1 From Prediction to Perspective: Designing Forecasting Lenses
8.2 NorthStar in Action—From Forecast Outputs to Decision Action
8.3 From Signals to Action—Designing Thresholds
8.4 From Models to Lenses—Interpreting Multiple Futures
8.5 Designing for Decision Robustness
8.6 From Forecasting Systems to Decision Systems
SkillBox 8: Building a Decision-Ready Forecasting System
LearningLab 8: Multi-Lens Forecasting and Decision Design
DesignStudio 8: Designing a Forecast-Driven Decision System
Mini-Case 8: Acting Under a Surge Scenario
Check Your Learning 8: Designing Decisions Under Forecast Uncertainty
Capstone Project: Forecast-by-Design
Part V Governance & Judgement
Chapter 9 Forecasting-by-Design
From Analytical Capability to Institutional Discipline
Opening Story: Forecasting for Climate Policy
9.1 From Forecasting to Decision Design
9.2 The Four Analytical Pillars as Decision Anchors
9.3 The Human Dimension in the Age of AI
9.4 The Forecasting-by-Design Cycle
SkillBox 9: Designing Decisions with Forecasts
LearningLab 9: Forecast Governance and Institutional Decision Design
DesignStudio 9: Designing a Forecast Governance System
Mini-Case 9: When Forecasts Disagree
Check Your Learning 9: Thinking in Time, Deciding by Design
Part VI Resources and Appendices
Appendix A Extensions of Explicit-Structure Forecasting
Appendix B Extensions of Implicit-Structure Forecasting
Appendix C Feature-Based Machine Learning Extensions
Appendix D Deep Learning and Sequence Models (Orientation Only)
Appendix E Choosing Forecasting Methods in Practice: A Decision Matrix
Data Dictionaries
Bibliography & Suggested Readings
Glossary
Index
Zhiwei Zhu, Ph.D. is a Clinical Associate Professor at Purdue University’s Daniels School of Business with expertise in statistics, mathematics, data science, and business analytics. He earned a Ph.D. in Statistics and an M.S. in Mathematics and previously served as a senior executive in the global reinsurance industry. A Fulbright U.S. Scholar, Dr. Zhu’s work focuses on how generative AI is transforming data science, decision-making, and business education. His research has been published in outlets including Harvard Data Science Review and INFORMS publications, combining academic research with industry experience to advance analytics education and practice.
Advances in data analytics and artificial intelligence have transformed forecasting by making sophisticated models faster, more accessible, and increasingly automated. However, while generating forecasts has become easier, making sound decisions under uncertainty remains a complex challenge. This book argues that the true value of forecasting lies not in producing predictions alone, but in designing systems that effectively translate imperfect forecasts into informed decisions. It introduces the concept of Forecast-by-Design, which shifts forecasting education from a focus on analytical techniques to a framework that integrates data, models, evaluation, trust, and decision-making within real-world organizational contexts.
The book also emphasizes the development of judgment, critical thinking, and decision capability alongside technical skills. Rather than treating AI as a replacement for human expertise, it presents AI as a learning and reasoning partner that supports analysis while preserving human responsibility and accountability. Through a structured learning approach and AI-supported activities, students progress from understanding forecasting concepts to designing and evaluating decisions under uncertainty. Ultimately, the book prepares learners to use forecasting responsibly by combining quantitative rigor, analytical reasoning, and sound decision design in an AI-enabled world.
Preface
How to Use This Book (For Instructors)
Part I Thinking in Time: The Logic of Forecasting
Chapter 1 The Logic of Time and Decision
Why Forecasting Is a Design Problem, Not a Modeling Task
Opening Story: The Oil Price Rollercoaster
1.1 Why Forecasting Matters in Business and Policy
1.2 Forecasting vs. Prediction: Thinking Through Time vs. Conditions
1.3 The Four Analytical Pillars of Modern Forecasting
1.4 Statistical Learning and Machine Learning: Two Ways to Build Trust
1.5 Structured vs. Unstructured Data: Two Forms of Evidence
1.6 AI and the Expansion of Forecasting Design
1.7 Time as Data: Trend, Seasonality, and Noise
1.8 Uncertainty and the Forecasting Decision Loop
1.9 Forecasting-by-Design
SkillBox 1: Seeing Demand Through Time
LearningLab 1: Thinking Through Time
DesignStudio 1: Designing a Forecast-Informed Decision Process
Mini-Case 1: Government Revenue Forecasting Under Uncertainty
Check Your Learning 1: Reasoning, Interpretation, and Design
Chapter 2 Smoothing Signals for Decision Sensemaking
Designing Fast, Interpretable Signals for Decisions
Opening Story: From Pandemic Curves to Pizza Crowds
2.1 Why Smoothing Supports Decision Sensemaking
2.2 How Smoothing Reveals Temporal Signals
2.3 Flat and Fading Memory: Moving Average and Exponential Smoothing
2.4 Choosing Responsiveness: Designing Memory for Decisions
2.5 Managerial Trade-Offs: Accuracy, Agility, and Trust
SkillBox 2: Smoothing for Direction, Not Prediction
LearningLab 2: Interpreting Smoothed Signals with AI
DesignStudio 2: Designing Directional Signals for Decisions
Mini-Case 2: Acting on Imperfect Signals
Check Your Learning 2: Smoothing for Direction, Not Prediction
Part II Modeling the Future: Foundations & Production
Chapter 3 Seeing Structure in Time
Decomposition as a Tool for Interpretation and Communication
Opening Story: Marriott’s Road Back to Full Occupancy
3.1 Decomposition as a Way of Thinking About Time
3.2 The Core Components of Temporal Structure
3.3 Additive and Multiplicative Structure: How Components Combine
3.4 Decomposition as a Communication Tool
SkillBox 3: Seeing Structure in Real Data
LearningLab 3: Reasoning About Structure with AI
DesignStudio 3: Designing Structure into Decision Systems
Mini-Case 3: Making Sense of Time in a New Context
Check Your Learning 3: Seeing Structure in Time
Chapter 4 Designing Visible Temporal Structure
Forecasting with Trend and Seasonality as Explicit Components
Opening Story: Tokyo Electric Power and the Cost of Misreading Visible Structure 9
4.1 From Seeing Structure to Designing It
4.2 What Explicit-Structure Forecasting Does
4.3 STL as a Representative Explicit-Structure Method
4.4 Additive and Multiplicative Thinking
4.5 The Explicit-Structure Forecasting Workflow
4.6 Business Interpretation: Why Visible Components Matter
4.7 Contrast Learning: Smoothing Vs. Explicit Forecasting
4.8 Boundary of the Chapter: What Visible Structure Cannot Resolve
SkillBox 4: Forecasting with Visible Structure Using STL
LearningLab 4: Reasoning with Explicit Structure
DesignStudio 4: Designing a Planning Response Around Visible Structure
Mini-Case 4: Choosing Whether Visible Structure Is Sufficient
Check Your Learning 4: Visible Temporal Structure in Forecast Design
Chapter 5 Designing Hidden Temporal Structure in Forecasting
Dependence, Memory, and Implicit Time Behavior
Opening Story: Grid Memory at Tokyo Electric Power
5.1 From Visible Structure to Hidden Structure
5.2 Dependence, Memory, and Shock Behavior
5.3 Why Stabilization Comes Before Dependence
5.4 Implicit Structure Through ARIMA/SARIMA
5.5 Comparing Explicit and Implicit Forecasting Design
SkillBox 5: Forecasting with Hidden Structure (ARIMA/SARIMA)
LearningLab 5: Using AI to Reason About Hidden Structure
DesignStudio 5: Designing Forecast Governance When Structure Is Hidden
Mini-Case 5: Choosing How to Handle Hidden Structure
Check Your Learning 5: Invisible Temporal Structure in Forecast Design
Chapter 6 Governing Forecasts Over Time
Forward Validation, Residual Signals, and Forecast Evolution
Opening Story: Airbnb’s Balancing Act—When Forecasts Lose Their Footing
6.1 Why Forecasts Fail Quietly
6.2 Accuracy and Reliability Are Not the Same Question
6.3 Residuals as Signals, Not Just Errors
6.4 Forward Validation—Watching Forecast Behavior as Time Moves Forward
6.5 Forecast Evolution—Maintain, Refit, or Rethink
SkillBox 6: Governing Forecasts Through Residual Signals
LearningLab 6: Using AI to Reason About Forecast Trust
DesignStudio 6: Designing a Forecast Governance Process
Mini-Case 6: When Forecast Trust Erodes
Check Your Learning 6: Governing Forecasts Over Time
Part III Forecasting in the Age of AI
Chapter 7 Forecasting Systems in the Age of AI
Extending Structure with Machine Learning and Generative Reasoning
Opening Story: The Moment Forecasting Changed at Netflix
7.1 From Box–Jenkins to Forecasting Systems in the Age of AI
7.2 Forecasting Systems in the Age of AI
7.3 Hybrid and Generative Forecasting Systems
7.4 Explainability, Bias, and Ethics in AI-Era Forecasting Systems
SkillBox 7: One Dataset, Four Forecasting Systems
LearningLab 7: Interpreting AI-Based Forecasting Systems
DesignStudio 7: Designing a Governed Hybrid Forecasting System
Mini-Case 7: When Forecasts Disagree: Designing Decisions Under AI Uncertainty
Check Your Learning 7: Forecasting Systems in the Age of AI
Part IV Workflow Integration
Chapter 8 Designing Decisions with Forecasts
An End-to-End Forecasting in Action, Accountability, and Uncertainty
(with a Capstone Project Assignment)
Opening Story: Forecasting Public Health Emergencies
8.1 From Prediction to Perspective: Designing Forecasting Lenses
8.2 NorthStar in Action—From Forecast Outputs to Decision Action
8.3 From Signals to Action—Designing Thresholds
8.4 From Models to Lenses—Interpreting Multiple Futures
8.5 Designing for Decision Robustness
8.6 From Forecasting Systems to Decision Systems
SkillBox 8: Building a Decision-Ready Forecasting System
LearningLab 8: Multi-Lens Forecasting and Decision Design
DesignStudio 8: Designing a Forecast-Driven Decision System
Mini-Case 8: Acting Under a Surge Scenario
Check Your Learning 8: Designing Decisions Under Forecast Uncertainty
Capstone Project: Forecast-by-Design
Part V Governance & Judgement
Chapter 9 Forecasting-by-Design
From Analytical Capability to Institutional Discipline
Opening Story: Forecasting for Climate Policy
9.1 From Forecasting to Decision Design
9.2 The Four Analytical Pillars as Decision Anchors
9.3 The Human Dimension in the Age of AI
9.4 The Forecasting-by-Design Cycle
SkillBox 9: Designing Decisions with Forecasts
LearningLab 9: Forecast Governance and Institutional Decision Design
DesignStudio 9: Designing a Forecast Governance System
Mini-Case 9: When Forecasts Disagree
Check Your Learning 9: Thinking in Time, Deciding by Design
Part VI Resources and Appendices
Appendix A Extensions of Explicit-Structure Forecasting
Appendix B Extensions of Implicit-Structure Forecasting
Appendix C Feature-Based Machine Learning Extensions
Appendix D Deep Learning and Sequence Models (Orientation Only)
Appendix E Choosing Forecasting Methods in Practice: A Decision Matrix
Data Dictionaries
Bibliography & Suggested Readings
Glossary
Index
Zhiwei Zhu, Ph.D. is a Clinical Associate Professor at Purdue University’s Daniels School of Business with expertise in statistics, mathematics, data science, and business analytics. He earned a Ph.D. in Statistics and an M.S. in Mathematics and previously served as a senior executive in the global reinsurance industry. A Fulbright U.S. Scholar, Dr. Zhu’s work focuses on how generative AI is transforming data science, decision-making, and business education. His research has been published in outlets including Harvard Data Science Review and INFORMS publications, combining academic research with industry experience to advance analytics education and practice.

