Base Profile

Robert Shiller

Nobel laureate who revealed asset bubbles and market irrationality through the CAPE ratio and narrative economics

Robert Shiller (born 1946) is Sterling Professor of Economics at Yale University and co-recipient of the 2013 Nobel Prize in Economics (with Fama and Hansen). He is one of the founders of behavioral finance, known for two major contributions: the CAPE (Cyclically Adjusted Price-to-Earnings) ratio — also known as the Shiller P/E — which smooths market valuations using 10-year average earnings and has become one of the most important predictors of long-term market returns; and Irrational Exuberance (2000), published at the peak of the internet bubble, which accurately warned of the impending crash, with a second edition in 2005 warning of the housing bubble. Shiller later developed Narrative Economics, arguing that economic behavior is driven by virally spreading stories and narratives, not just rational expectations. He co-created the Case-Shiller Home Price Index with Karl Case, the most authoritative tracker of US home prices.

Behavioral EconomicsFinancial MarketsMacroeconomicsEconomic TheoryEra 1972-至今Influence 91

Controversy TagsWhether CAPE remains valid in low-interest-rate environments ('permanently overvalued' debate)Fundamental disagreement with Fama's Efficient Market HypothesisFalsifiability debate over narrative economics

Thought System

Core Knowledge Graph

Core Beliefs

Financial Markets Are Driven by Irrational Factors and Prices Persistently Deviate from Fundamentals

Contrary to the Efficient Market Hypothesis, Shiller argues that investor psychology, herding behavior, and emotional narratives cause asset prices to persistently and significantly deviate from intrinsic value. This deviation is not brief noise but a systematic phenomenon that can persist for years or even decades.

Source: Irrational Exuberance, Robert Shiller, Princeton University Press, 2000 (3rd ed. 2015) / Do Stock Prices Move Too Much to Be Justified by Subsequent Changes in Dividends?, Robert Shiller, American Economic Review, 1981

CAPE Is the Most Reliable Single Indicator for Predicting Long-Term Market Returns

By dividing market price by the 10-year average real earnings (eliminating business cycle volatility), CAPE provides a more stable valuation metric. Historical data shows high CAPE (e.g., above 30) is highly correlated with low returns over the following decade, while low CAPE portends high returns. But CAPE cannot predict short-term movements; it only has statistical significance for long-term predictions of 10+ years.

Source: Stock Prices, Earnings, and Expected Dividends, Campbell & Shiller, Journal of Finance, 1988 / Valuation Ratios and the Long-Run Stock Market Outlook, Campbell & Shiller, Journal of Portfolio Management, 1998

Economic Behavior Is Driven by Virally Spreading Narrative Stories

Economic events are determined not just by data and rational expectations, but by stories and narratives that spread through society. These narratives infect populations like viruses, changing consumption, investment, and saving behavior. Understanding the propagation of narratives is key to understanding economic fluctuations; economics needs to incorporate epidemiology and psychology.

Source: Narrative Economics: How Stories Go Viral and Drive Major Economic Events, Robert Shiller, Princeton University Press, 2019 / Narrative Economics, Presidential Address, American Economic Association, 2017

Financial Innovation Should Serve Social Risk Management, Not Merely Create Profits

The true value of financial markets lies in helping society diversify and manage risks, including housing risk, income risk, and country risk. Shiller advocates creating new financial instruments (such as GDP-linked bonds, housing price futures) to address societal risks, not merely serve speculation.

Source: The New Financial Order: Risk in the 21st Century, Robert Shiller, Princeton University Press, 2003 / Finance and the Good Society, Robert Shiller, Princeton University Press, 2012

Real Estate Prices Are Subject to Irrational Bubbles and Cannot Outpace Inflation Long-Term

Shiller's historical data research shows that inflation-adjusted US residential home prices showed virtually no real growth over the 100 years from 1890-1990. The 2000s home price surge was a classic irrational bubble, driven by optimistic narratives and loose credit rather than fundamental support.

Source: Irrational Exuberance, 2nd edition, Robert Shiller, Princeton University Press, 2005 / Case-Shiller Home Price Indices historical data, S&P/Case-Shiller, ongoing

Mental Models

CAPE Shiller P/E Ratio

Divide current market price by the 10-year average real earnings to eliminate business cycle noise, yielding a more reliable market valuation metric for determining whether markets are in bubble territory.

At end of 1999, the US stock market CAPE reached 44, nearly 3 times the historical mean (about 16). Shiller warned in Irrational Exuberance this portended extremely low returns over the next decade. The S&P 500's real return from 2000-2010 was near zero, fully confirming CAPE's prediction.

Long-Term Asset AllocationMarket Valuation AssessmentRetirement PlanningMacro Investment Decisions

Narrative Contagion Model

Analogize the spread of economic narratives to the epidemiological SIR model (Susceptible-Infected-Recovered), analyzing how specific economic stories spread through populations, peak, then recede, thereby affecting macroeconomic behavior.

The late 1990s 'New Economy' narrative (the internet will transform everything, traditional valuation methods are obsolete) spread like a virus, infecting millions of investors and driving the Nasdaq bubble. The collapse of the narrative and the bubble burst occurred almost simultaneously.

Bubble IdentificationMacroeconomic AnalysisInvestor Sentiment AssessmentMedia Influence Analysis

Excess Volatility Test

If stock prices are rational discounts of future dividends, price volatility should be less than the actual variation in dividends; but empirical data shows price volatility far exceeds dividend volatility, proving systematic irrationality in markets.

In his 1981 American Economic Review paper, Shiller found that US stock market price volatility was about 5-13 times the magnitude of dividend changes — this 'excess volatility' cannot be explained by rational expectations models, becoming one of the most important empirical challenges to the Efficient Market Hypothesis.

Market Efficiency AssessmentBehavioral Finance ResearchAsset Pricing AnalysisAcademic Research Methods

Values & Paradoxes

Data-Driven Empirical Research

Finance in Service of Public Good

Interdisciplinary Thinking

Shared Nobel Prize with Fama Despite Holding Diametrically Opposed Market Views

The 2013 Nobel Prize in Economics was awarded simultaneously to Shiller and Fama — the former arguing markets exhibit systematic irrationality and predictable bubbles, the latter the founder of the Efficient Market Hypothesis who believes markets are basically efficient. This rare case of shared prize with opposing views reflects a fundamental disagreement in economics about the nature of markets.

Can Identify Bubbles But Cannot Precisely Predict Crash Timing

Shiller publicly warned of irrational exuberance in stocks as early as 1996, but markets rose for another 4 years before crashing. He warned of the housing bubble in 2005, but the crash didn't come until 2007-2008. Identifying the existence of a bubble and predicting its timing are two entirely different problems — Shiller maintains clear awareness of this distinction.

Evolution Phases

Academic Foundation

1972-1990

Establishing excess volatility theory, challenging the empirical foundations of the Efficient Market Hypothesis

After completing his PhD at MIT, Shiller began systematically studying the deviation between actual financial market volatility and rational expectations models. The 1981 excess volatility paper was the peak of this phase, directly challenging the then-dominant Efficient Market Hypothesis.

CAPE Indicator Development

1988-2000

Collaborating with John Campbell to develop CAPE, building an actionable market valuation tool

Shiller's collaboration with John Campbell produced CAPE (Cyclically Adjusted Price-to-Earnings), translating academic theory into an actionable market valuation metric. The 2000 publication of Irrational Exuberance brought CAPE into public view and issued one of the most accurate warnings at the peak of the internet bubble.

Housing Bubble Warning

2000-2010

Creating the Case-Shiller Home Price Index, warning of the housing bubble, mainstreaming behavioral finance

Shiller collaborated with Karl Case to create the Case-Shiller Home Price Index, becoming the authoritative tool for tracking US home prices. In the 2005 second edition of Irrational Exuberance, he extended his analysis to real estate, explicitly warning of the 2007-2008 housing crash. The 2013 Nobel Prize was the highest recognition of this phase's academic accumulation.

Narrative Economics Founding

2015-至今

Proposing narrative economics theory, incorporating stories and narratives into economic analysis frameworks

Shiller formally proposed narrative economics in his 2017 American Economic Association presidential address, publishing the eponymous book in 2019. This theory integrates economics with epidemiology, psychology, and communication studies, representing his latest contribution to economic methodology.

Methodology Cards

3 Callable Cards

CAPE Valuation Application Framework

shiller-card-cape-application

Use CAPE to assess overall market valuation levels as a reference for long-term asset allocation decisions, not as a short-term market timing tool.

Step 1: Look up current CAPE value — available at Shiller's Yale data page (econ.yale.edu/~shiller/data.htm)
Step 2: Compare with historical mean — US stock market historical CAPE mean is about 16-17; above 25 is elevated, above 30 is overvalued, above 35 is extremely overvalued
Step 3: Estimate 10-year forward returns — the higher the CAPE, the lower the expected return over the next decade; historical data shows a correlation of about -0.6 between CAPE and returns 10 years later
Step 4: Adjust asset allocation — when CAPE is extremely high, modestly reduce equity allocation and increase bonds or other assets; but don't try to time precisely, only make directional adjustments

Stock-bond ratio decisions for long-term retirement portfoliosDetermining whether in a bubble environmentCross-country relative valuation comparisons

Anti-Patterns

Using CAPE to predict short-term (1-3 year) market movements — CAPE has no short-term predictive power
Directly comparing absolute CAPE values with historical means without considering changes in the interest rate environment
Completely liquidating stocks at high CAPE levels, missing potential continued gains

Asset Bubble Identification Checklist

shiller-card-bubble-checklist

Systematically determine whether an asset is in bubble territory by checking multiple dimensions including price deviation from fundamentals, narrative propagation, media coverage, and retail participation.

Step 1: Check valuation deviation — does the current price deviate more than two standard deviations from the historical mean? Is CAPE or other valuation metrics at historical extremes?
Step 2: Track narrative propagation — is there a widely spreading 'this time is different' narrative? Has media coverage of the asset increased abnormally?
Step 3: Observe retail participation — are non-professional investors flooding in? Is there obvious 'chasing gains' behavior?
Step 4: Check credit expansion — is there widespread borrowing to invest in the asset? Has leverage risen significantly?

Assessing whether current stock markets are in a bubbleAnalyzing investment enthusiasm for specific sectors or themesDeveloping risk management strategies for major asset allocation

Anti-Patterns

Equating bubble identification with precisely predicting crash timing — these are different problems
Using only a single indicator (e.g., CAPE) to judge bubbles, ignoring other dimensions
Immediately shorting after bubble identification, ignoring the reality that bubbles can persist for years

Economic Narrative Analysis Method

shiller-card-narrative-analysis

Identify the currently dominant economic narratives, track their propagation paths and emotional intensity, to anticipate market sentiment shifts and collective changes in economic behavior.

Step 1: Identify dominant narratives — what is the most widely spreading story in current markets? (e.g., 'AI will transform everything', 'home prices only go up')
Step 2: Track propagation intensity — assess the breadth of narrative spread through media coverage frequency, social media discussion volume, search trends
Step 3: Analyze narrative logic — is the narrative internally consistent? Can it explain all counterexamples? Overly perfect narratives are often warning signs
Step 4: Find narrative cracks — are there data or events contradicting the dominant narrative? Is the narrative's spread beginning to decelerate?

Analyzing current market sentiment and investor psychologyEvaluating the long-term investment value of a sector or assetUnderstanding the social acceptance of macroeconomic policies

Anti-Patterns

Substituting narrative analysis for quantitative valuation analysis — they should complement, not replace each other
Believing a narrative is correct because it is widely spread
Ignoring narrative inertia — even when a narrative begins to decline, its influence may persist for years

Decision Timeline

9 Key Events

1946

Born in Detroit

Context: Robert Shiller was born in Detroit, Michigan, growing up during the rapid post-war expansion of the American economy, an environment that cultivated his early interest in economic cycles and market volatility.

Decision: Developed early interest in economics and mathematics

Reasoning: Post-war prosperity and subsequent economic fluctuations provided intuitive economics education

Outcome: Pursued an academic career in economics

Lesson: Experiencing economic cycles firsthand is an important foundation for forming long-term economic views

1972

Received PhD in Economics from MIT

Context: Shiller completed his PhD at MIT under Franco Modigliani (Nobel laureate), receiving rigorous mathematical economics training while beginning to question the limitations of rational expectations models.

Decision: Chose to study empirical behavior of financial markets rather than pure theoretical modeling

Reasoning: Observed systematic deviations between actual market behavior and rational expectations theory predictions

Outcome: Established methodological foundations for incorporating psychology and behavior into financial research

Lesson: Top academic training and critical questioning of orthodox theory can coexist and produce breakthrough research

1981

Published Excess Volatility Paper, Challenging the Efficient Market Hypothesis

Context: Shiller published 'Do Stock Prices Move Too Much to Be Justified by Subsequent Changes in Dividends?' in the American Economic Review, using empirical data to prove stock price volatility far exceeds rational pricing model predictions, becoming one of the most important empirical challenges to the Efficient Market Hypothesis.

Decision: Used simple but rigorous empirical methods to directly test the core predictions of the Efficient Market Hypothesis

Reasoning: If markets are efficient, prices should equal the rational discount of future dividends, and price volatility should not exceed actual dividend changes

Outcome: The paper became one of the most cited papers in behavioral finance, directly contributing to the establishment of the field

Lesson: Simple, clear empirical tests can drive paradigm shifts more effectively than complex theoretical models

1988

Collaborated with Campbell to Develop CAPE Shiller P/E Ratio

Context: Shiller and John Campbell published a paper in the Journal of Finance proposing the use of 10-year average real earnings to calculate P/E ratios (i.e., CAPE), proving this indicator has significant predictive power for stock market returns over the next decade, far superior to traditional single-year P/E ratios.

Decision: Translated academic research findings into an actionable market valuation tool

Reasoning: Single-year earnings are too influenced by business cycles; smoothing 10-year earnings provides a more stable valuation benchmark

Outcome: CAPE became one of the most widely used long-term market valuation indicators globally; Shiller regularly publishes updated data on the Yale University website

Lesson: Converting academic tools into publicly available data services can greatly expand the social impact of research

1996

Submitted Irrational Exuberance Warning to Fed Chairman Greenspan

Context: Shiller submitted a research report to the Federal Reserve Board warning of irrational exuberance in stock markets. Greenspan subsequently delivered his famous 'irrational exuberance' speech in December 1996, a phrase that later became the title of Shiller's 2000 book.

Decision: Directly submitted academic research findings to policymakers, attempting to influence monetary policy

Reasoning: The social harm of market bubbles requires policy-level attention and cannot remain only in academic discussion

Outcome: Greenspan adopted the phrase 'irrational exuberance' but the Fed took no substantial action; markets continued rising for 4 more years

Lesson: Identifying a bubble and stopping a bubble are two different problems; policy tools are extremely limited in countering market sentiment

2000

Published Irrational Exuberance, Accurately Warning of the Internet Bubble

Context: Irrational Exuberance was published in March 2000, just days after the Nasdaq reached its all-time high. In the book, Shiller systematically explained how the CAPE indicator, psychological factors, and media narratives jointly drove the internet bubble, warning that a crash was inevitable.

Decision: Published a warning book at the peak of the bubble, taking the risk of being mocked by market participants

Reasoning: Academic responsibility requires issuing warnings when there is sufficient evidence, even if short-term market movements may seem to 'disprove' them

Outcome: The internet bubble immediately burst; Irrational Exuberance became the most important popular work in behavioral finance, establishing Shiller's reputation as a forecaster

Lesson: Long-term predictions based on rigorous analysis will ultimately be validated, even if questioned in the short term

2005

Second Edition of Irrational Exuberance Warned of Housing Bubble

Context: Shiller added analysis of the real estate market in the second edition of Irrational Exuberance, pointing out that US home prices had severely deviated from historical trends and fundamentals, with Case-Shiller Index data showing classic bubble characteristics.

Decision: Extended the analytical framework from stock markets to real estate markets

Reasoning: Real estate markets are equally subject to irrational exuberance, with greater harm because the primary asset of ordinary families is their home

Outcome: The 2007-2008 housing crash fully validated Shiller's warning; he became one of the few economists to accurately predict two bubbles

Lesson: The same behavioral finance principles apply to different asset classes; bubble identification frameworks have cross-asset universality

2013

Awarded Nobel Prize in Economics

Context: Shiller shared the 2013 Nobel Prize in Economics with Eugene Fama and Lars Hansen, recognizing their contributions to the empirical analysis of asset prices. Shiller's award was primarily for his research on the predictability of asset prices, particularly CAPE and excess volatility theory.

Decision: Accepted sharing the Nobel Prize with Fama, despite their diametrically opposed positions on market efficiency

Reasoning: The Nobel Committee believed both diametrically different market theories had made important contributions to asset price research

Outcome: The Nobel Prize brought Shiller's behavioral finance theory to the widest public attention, further advancing the mainstreaming of behavioral economics

Lesson: The fundamental disagreement in economics about the nature of markets remains unresolved; both theoretical frameworks have their explanatory power and limitations

2017

Proposed Narrative Economics in AEA Presidential Address

Context: Shiller formally proposed narrative economics theory in his American Economic Association annual meeting presidential address, arguing that economics needs to systematically study how virally spreading stories and narratives influence macroeconomic behavior, introducing the epidemiological SIR model to analyze narrative propagation.

Decision: Proposed a completely new economic methodology framework late in his career, challenging the basic assumptions of mainstream economics

Reasoning: Traditional economic models cannot explain many important economic phenomena; it is necessary to introduce narratives and stories as a neglected variable

Outcome: Narrative economics opened a new research direction at the intersection of economics, communication studies, and psychology; the eponymous book was published in 2019

Lesson: Innovations in economic methodology often come from incorporating tools and frameworks from other disciplines

Reading List

Books

Recommended by (1)

Thinking, Fast and Slow

Daniel Kahneman · 2011

Shiller included Kahneman's book in the recommended reading of Irrational Exuberance, 3rd edition (2015), and listed it as required reading in his Yale University Financial Markets course (open course), calling it 'the most complete psychological foundation for understanding irrational investor behavior'.

Amazon 当当

Written by (4)

Irrational Exuberance

Robert Shiller · 2000

Shiller's own landmark work, published at the peak of the internet bubble, systematically explaining the psychological and social drivers of asset bubbles. Shiller has stated in multiple interviews that the purpose of writing the book was 'to help the public understand they were experiencing not a normal market but a historic bubble'.

Amazon 当当

Narrative Economics

Robert Shiller · 2019

Shiller's late-career landmark work proposing narrative economics theory. At the 2019 Princeton University Press launch event, Shiller stated, 'This book represents the most important intellectual shift of my career; it tells us that economics needs to study the spread of stories the way epidemiologists study the spread of viruses'.

Amazon 当当

The New Financial Order: Risk in the 21st Century

Robert Shiller · 2003

Written by Shiller himself, proposing the use of financial innovation to address societal risk problems. Shiller has repeatedly emphasized in the book and subsequent interviews that 'the true mission of financial markets is to help ordinary people manage the biggest risks in their lives — unemployment, illness, home price declines — not to make a few people fabulously wealthy'.

Amazon 当当

Animal Spirits

George Akerlof and Robert Shiller · 2009

Co-authored by Shiller and George Akerlof, systematizing Keynes's 'animal spirits' concept. Shiller described the book in a Harvard lecture (2009) as 'an attempt to extend behavioral economics from the micro level to macroeconomic policy'.

Amazon 当当

Influence Network

Origins, Contemporaries & Legacy

Influenced By

Franco Modigliani · Mentor Influence

Nobel laureate Modigliani was Shiller's doctoral advisor, cultivating his rigorous mathematical approach and macroeconomic perspective on financial markets

George Akerlof · Academic Collaboration

Shiller co-authored Animal Spirits with Akerlof, systematizing Keynes's 'animal spirits' concept into a behavioral macroeconomics framework

John Maynard Keynes · Intellectual Heritage

Keynes's 'animal spirits' and emphasis on market irrationality were important precursors to Shiller's behavioral finance thinking

Influenced

Behavioral Finance Field · Field Foundation

Shiller's excess volatility research was a key empirical foundation for establishing behavioral finance, influencing the entire field's development direction

Global Long-Term Investors · Practical Tool Provision

The CAPE indicator is widely used by institutional and individual investors globally, becoming a standard reference tool for long-term asset allocation decisions

Co-thinkers

George Akerlof · Co-authorship

Co-authored Animal Spirits, jointly advancing behavioral macroeconomics

Richard Thaler · Behavioral Economics Colleague

Together with Thaler advanced behavioral economics from the fringe to the mainstream; both received the Nobel Prize in Economics

Peer Reviews

Shiller's work on excess volatility changed the way economists think about financial markets. Before his 1981 paper, the efficient market hypothesis was essentially unchallenged. After it, we had to take seriously the possibility that markets could be systematically wrong.
John Y. Campbell · Introduction to Shiller's collected works, Princeton University Press, 2014

Robert Shiller is the most important critic of the efficient market hypothesis. His CAPE ratio and his work on bubbles have proven more useful for investors than almost any other academic contribution.
Jeremy Grantham · GMO Quarterly Letter, Q1 2014

正在打开人物节点

Robert Shiller

Core Knowledge Graph

Core Beliefs

Financial Markets Are Driven by Irrational Factors and Prices Persistently Deviate from Fundamentals

CAPE Is the Most Reliable Single Indicator for Predicting Long-Term Market Returns

Economic Behavior Is Driven by Virally Spreading Narrative Stories

Financial Innovation Should Serve Social Risk Management, Not Merely Create Profits

Real Estate Prices Are Subject to Irrational Bubbles and Cannot Outpace Inflation Long-Term

Mental Models

CAPE Shiller P/E Ratio

Narrative Contagion Model

Excess Volatility Test

Values & Paradoxes

Shared Nobel Prize with Fama Despite Holding Diametrically Opposed Market Views

Can Identify Bubbles But Cannot Precisely Predict Crash Timing

Evolution Phases

Academic Foundation

CAPE Indicator Development

Housing Bubble Warning

Narrative Economics Founding

9 Key Events

Born in Detroit

Received PhD in Economics from MIT

Published Excess Volatility Paper, Challenging the Efficient Market Hypothesis

Collaborated with Campbell to Develop CAPE Shiller P/E Ratio

Submitted Irrational Exuberance Warning to Fed Chairman Greenspan

Published Irrational Exuberance, Accurately Warning of the Internet Bubble

Second Edition of Irrational Exuberance Warned of Housing Bubble

Awarded Nobel Prize in Economics

Proposed Narrative Economics in AEA Presidential Address

Books

Recommended by (1)

Written by (4)

Origins, Contemporaries & Legacy

Influenced By

Influenced

Co-thinkers

Peer Reviews