Chapter 37 Exercises: Portfolio Thinking

How to Use These Exercises

The centerpiece of this chapter's exercises is the Luck Portfolio Mapping Exercise (Exercise 3), which asks you to map your current life portfolio using the frameworks from the chapter. Build toward it through Levels 1 and 2, then extend your analysis in Levels 4 and 5.

Level 1: Comprehension and Recall

Exercise 1.1 — Portfolio Vocabulary

Define each of the following terms in your own words, as applied to life portfolio design (not financial investment):

a) Diversification b) Luck correlation c) Barbell strategy d) Concentrated bet e) Explore/exploit tension f) Rebalancing g) Risk tolerance

Exercise 1.2 — Markowitz's Four Principles

The chapter summarizes four core principles from modern portfolio theory and shows how each translates to life design. In your own words, state each principle and its life-design application. Then rate how well you think each principle translates (1 = doesn't translate well, 5 = translates perfectly). Explain your ratings.

Exercise 1.3 — The Multi-Armed Bandit

Describe the multi-armed bandit problem and its core dilemma. Then answer: a) What does the multi-armed bandit problem suggest about the right time in life to explore versus exploit? b) What is "regret" in the multi-armed bandit framework, and why might regret minimization be a better life decision criterion than expected-value maximization? c) Finding 2 in the chapter says "pure exploitation is almost never optimal." Explain why this is true mathematically, and give one real-life example where someone over-exploited and paid a cost.

Exercise 1.4 — Marcus's Portfolio Analysis

Review Marcus's portfolio table from Part VII of the chapter. In your own words: a) Why was Marcus's portfolio highly concentrated? b) Why is the college + startup combination a barbell, rather than a compromise? c) What specific information did the portfolio framework provide that a simple pros-and-cons list would not?

Level 2: Application and Analysis

Exercise 2.1 — Luck Correlation Analysis

Consider the following pairs of life domains. For each pair, estimate the likely luck correlation (strongly positive, weakly positive, uncorrelated, weakly negative, strongly negative) and explain the mechanism:

a) Primary career domain + financial domain b) Physical health + career performance c) Close relationships + career stress d) Side creative project + primary career e) Geographic location + professional network f) Skill development + job security

Exercise 2.2 — The Barbell Test

For each of the following life situations, diagnose whether the person is running a barbell, a concentrated bet, pure exploitation, or the mediocre middle. Explain your reasoning and suggest a portfolio redesign for each:

a) A 20-year-old who is entirely focused on studying for pre-med exams, has no side projects or exploration, and plans to start exploring only after becoming a doctor b) A 25-year-old who has a stable day job, runs a small side creative business, maintains a wide network across two fields, and invests in skills in both domains c) A 22-year-old who has quit their job to pursue a startup with no stable income, limited savings, and no fallback plan d) A 24-year-old who has a "decent" job they don't love but don't dislike, does "some" networking but nothing systematic, has "a few" side interests but doesn't invest deeply in any of them

Exercise 2.3 — The Optimal Stopping Problem

The chapter describes the 37% rule from optimal stopping theory. Apply it to your own situation: a) How many years of career exploration do you expect to have before you need to commit deeply to a primary path? b) By the 37% rule, how long should you spend in pure exploration mode? c) What does "exploration" specifically mean for your current life situation — what activities count? d) Are you currently exploring more or less than the 37% rule suggests? What would it look like to optimize this?

Exercise 2.4 — Portfolio Drift Identification

The chapter describes four common drift patterns: exploitation creep, stability erosion, network concentration, and risk accumulation. Identify which drift pattern is most likely to affect you over the next five years if you do nothing to prevent it. Write: a) Which drift pattern and why it's the likely one b) The specific mechanism through which this drift would occur in your life c) One specific structural protection you could build now to prevent it

Level 3: The Luck Portfolio Mapping Exercise

The centerpiece exercise. Take 45–60 minutes. Be honest about your current portfolio — not the portfolio you aspire to.

Step 1: Identify Your Life Domains

List your primary life domains. Use the chapter's list as a starting point (Career/Work, Education, Financial, Health, Relationships, Creative/Side Projects, Geographic/Environmental) and add or modify as relevant to your situation.

My primary life domains: 1. __ 2. __ 3. __ 4. __ 5. __ 6. __ 7. ___

Step 2: Assess Each Domain's Current State

For each domain, complete the following:

Domain: ___

• Current investment level (Low / Medium / High / Very High):
• Expected return (what you get from this domain):
• Current risk level (Low / Medium / High / Very High):
• Luck physics in this domain (how much does luck influence outcomes vs. consistent effort?):
• One word that describes the current health of this domain:

(Repeat for each domain)

Step 3: Map Luck Correlations

Create a simple correlation matrix for your domains. For each pair, mark: + = positively correlated luck (they rise and fall together) 0 = uncorrelated luck – = negatively correlated luck

Correlation analysis: - Which domains are most correlated? (Most concentrated exposure?) - Which domains are most uncorrelated or negatively correlated? (Best natural diversifiers?) - If your single highest-risk domain collapsed, which other domains would be most affected?

Step 4: Identify Your Portfolio Structure

Based on your analysis, characterize your current portfolio:

Is your portfolio predominantly: - [ ] Highly concentrated (most investment in 1–2 correlated domains) - [ ] Moderately diversified (investment across 3–4 domains, some correlation) - [ ] Well diversified (investment across 5+ domains, meaningful uncorrelated exposure) - [ ] Barbelled (strong investment in both very safe and very risky domains) - [ ] Mediocre-middle dominated (most investment in medium-risk, medium-return domains)

Explore/exploit ratio: Estimate what percentage of your current time, energy, and investment is: - Pure exploration (trying genuinely new domains, relationships, skills): % - Pure exploitation (deepening known-good investments): % - Maintenance (keeping existing investments stable): ___%

Is this ratio appropriate for your current life stage? Why or why not?

Step 5: Design Your Target Portfolio

Based on your current portfolio analysis, design the portfolio you would want to have in 12 months:

Target invest-more domains: (Where should you be investing more than you currently are?) 1. __ Why: __ 2. __ Why: __

Target invest-less domains: (Where are you over-invested relative to the returns?) 1. __ Why: __

Diversification additions: (What genuinely new, uncorrelated domain could you add to reduce concentration risk?)

Barbell design: (What is your stable base? What is your high-variance exploratory bet?) - Stable base: __ - Exploratory bet: __

Explore/exploit target ratio: ___ % exploration / ___ % exploitation

Step 6: Three Specific Portfolio Actions

Based on your analysis, identify three specific actions you will take in the next 60 days to move toward your target portfolio:

Level 4: Synthesis and Design

Exercise 4.1 — The Portfolio for Different Life Stages

Design a luck portfolio for three different life stages: a) An 18-year-old entering college with no clear career direction b) A 28-year-old with 5 years in a career who wants to make a significant pivot c) A 45-year-old mid-career professional with family obligations and a mortgage

For each stage, specify: optimal explore/exploit ratio, appropriate use of barbell strategy, key diversification priorities, and risk tolerance calibration factors.

Exercise 4.2 — The Barbell Under Stress

One challenge of the barbell strategy is that in difficult periods, people tend to collapse the barbell toward the safe end — abandoning exploration and retreating to exploitation. Design a "barbell preservation protocol" — a set of specific rules or commitments that would protect your exploratory investments during stressful periods when you'd naturally be tempted to abandon them.

Exercise 4.3 — The Portfolio Rebalancing Trigger System

Design a concrete rebalancing system for your luck portfolio. Specify: a) What specific metrics or observations would trigger a portfolio review? (Not just "calendar dates" but actual signals that your portfolio has drifted) b) What the rebalancing process would look like — what questions would you ask and what decisions would you make? c) Who else would be involved in your rebalancing process, and why?

Exercise 4.4 — The Negatively Correlated Bet

Identify one negatively correlated investment you could make in your life portfolio — something that performs well specifically when your primary domain performs badly. Write: a) What this investment is b) Why it's negatively correlated with your primary domain c) What it would cost to establish this hedge d) Whether the insurance value is worth the cost, and why

Level 5: Research and Advanced Application

Exercise 5.1 — Portfolio Theory Limits

Modern portfolio theory has well-documented limitations when applied to financial markets. Research two of the following critiques and apply them to life portfolio design:

a) Fat tails / non-normal distributions (how does this affect life portfolio diversification?) b) Correlation instability (correlations between life domains may shift during crises — how does this affect the diversification strategy?) c) The Kelly Criterion vs. mean-variance optimization (when should you bet more than a diversified portfolio suggests?) d) Behavioral portfolio theory (people don't optimize portfolios — they have "mental accounts" — how does this apply to life domain management?)

Exercise 5.2 — The Explore/Exploit Literature

Research the following three papers or results from the multi-armed bandit / explore-exploit literature and write a paragraph connecting each to life portfolio management:

a) The Thompson Sampling algorithm (a Bayesian approach to exploration that updates beliefs based on evidence) b) The Gittins Index (a mathematical framework for optimal allocation under uncertainty) c) The "upper confidence bound" exploration strategy (explore options about which you are uncertain, in proportion to your uncertainty)

Exercise 5.3 — Taleb's Antifragility vs. Resilience

Taleb distinguishes between three types of systems: fragile (harmed by disorder), resilient (unchanged by disorder), and antifragile (benefited by disorder). Apply these three categories to life portfolio design:

a) What would a fragile life portfolio look like? Give a specific example. b) What would a resilient life portfolio look like? Give a specific example. c) What would an antifragile life portfolio look like — a portfolio that actually benefits from lucky and unlucky variance? Give a specific example. d) Is antifragility a realistic goal for individuals? What would it require?

Exercise 5.4 — The Cross-Domain Portfolio Study

Design a research study that would test whether people who apply portfolio thinking to their life domains have better outcomes than those who don't. Specify: a) How you would define and measure "portfolio thinking" in life design b) How you would measure "better outcomes" (career, wellbeing, luck outcomes — and how you'd measure "luck outcomes" specifically) c) What comparison groups you'd use d) What the key confounds are, and how you'd address them e) What findings would most strongly support the portfolio thinking hypothesis, and what would most strongly undermine it?