Market Liquidity

One-Sentence Definition

The ability for supply and demand to match quickly enough is the key to the viability of a market-based product.

What Problem Does It Solve

It helps you determine how a product is understood, chosen, substituted, and disseminated.

More specifically, Market Liquidity is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? If I want to make a better choice, which variable, which path, and which constraint should I look at first?

Maslow’s Hierarchy of Needs

One-Sentence Definition

Human needs are divided into five levels, from physiological to self-actualization, and higher-level needs are pursued only after lower-level needs are satisfied.

Core Concept

Five levels of needs: Physiological needs → Safety needs → Social needs → Esteem needs → Self-actualization needs. Lower-level needs take priority.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps you shift your judgment from intuition to structured analysis.

MECE Principle

One-Sentence Definition

When categorizing, ensure mutual exclusivity and collective exhaustiveness—no overlap, no omission.

Core Concept

MECE stands for Mutually Exclusive, Collectively Exhaustive. A core McKinsey methodology: when breaking down a problem, ensure that the parts do not overlap and that together they cover the entire scope.

What Problem Does It Solve

When information is incomplete, options are many, or risks are unclear, it helps shift your judgment from intuition to structured analysis.

Mental Models

One-Sentence Definition

A simplified framework that people use to understand the world, explain phenomena, and make decisions.

What Problem Does It Solve

It helps you identify blind spots, biases, and oversimplifications in your thinking.

More specifically, mental models are suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, path, or constraint should I look at first?

Metacognition

One-Sentence Definition

Observing and regulating your own thought process, rather than just focusing on the conclusion.

Core Concept

Metacognition is “cognition about cognition,” including knowing what you know, what you don’t know, and how to adjust your learning and thinking strategies.

What Problem Does It Solve

It helps you get feedback faster, correct your methods, and build long-term capabilities.

More specifically, metacognition is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, which path, or which constraint should I look at first?

Metcalfe’s Law

One-Sentence Definition

The value of a network is proportional to the square of the number of its users—the more users, the greater the value.

Core Concept

Metcalfe’s Law: The value of a network equals the square of the number of users. A network of 10 people has a value of 100, while a network of 100 people has a value of 10,000. This explains the network effect of social networks.

Zoom-Out Thinking

One-Sentence Definition

Step back to see the big picture, understanding the full scope of a problem from a broader perspective.

Core Concept

Zoom-out thinking means pulling your perspective back to see the overall structure and major trends of a situation, avoiding the trap of missing the forest for the trees.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps shift your judgment from intuition to structured analysis.

MVP Minimum Viable Product

One-Sentence Definition

Validate key assumptions with the smallest possible solution, rather than building a complete product all at once.

What Problem Does It Solve

It helps you design clearer user paths, choice structures, and information hierarchies.

More specifically, the MVP Minimum Viable Product is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? If I want to make a better choice, which variable, which path, or which constraint should I look at first?

Moat Theory

One-Sentence Definition

A company’s sustainable competitive advantage is like a castle’s moat—the wider and deeper it is, the harder it is to breach.

Core Concept

Buffett introduced the concept of the moat: intangible assets (brands/patents), switching costs, network effects, and cost advantages are four common types of moats.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps pull your judgment from intuition back to structured analysis.

Multi-Dimensional Perspective

One-Sentence Definition

Examining the same issue from multiple dimensions and angles to avoid the limitations of a single perspective.

Core Concept

A multi-dimensional perspective requires us to analyze problems from various dimensions such as time, space, roles, and hierarchy. Any judgment based on a single dimension is likely to be one-sided.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps pull your judgment back from intuition to structured analysis.

Mushroom Management

One-Sentence Definition

Like cultivating mushrooms—growing in darkness, unnoticed, but this is precisely the phase of building strength.

Core Concept

Mushroom Management teaches us: the early stages of a career or endeavor are like mushrooms, unnoticed in the dark. This phase is a critical period for accumulating skills and laying a foundation.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps shift your judgment from intuition back to structured analysis.

Network Effects

One-Sentence Definition

The value of a product increases as more users join.

What Problem Does It Solve

It helps you break down growth into observable, diagnosable, and optimizable stages.

More specifically, Network Effects is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? If I want to make a better choice, which variable, which path, and which constraint should I look at first?

Nine-Grid Thinking

One-Sentence Definition

Use a 3×3 matrix to decompose and organize ideas, turning complex problems into structured ones.

Core Concept

The nine-grid breaks a big problem into nine small modules, helping to comprehensively cover all aspects. The center cell is usually the core theme, while the eight surrounding cells are related elements.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps shift your judgment from intuition to structured analysis.

Non-SR Thinking

One-Sentence Definition

Insert thinking between stimulus and response, shifting from passive reaction to active choice.

Core Concept

SR refers to the stimulus-response model. Non-SR thinking adds a thinking process between stimulus and response, i.e., stimulus → thinking → response, shifting from passive reaction to active, deliberate response.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps pull your judgment from intuition back to structured analysis.

Nonlinear Thinking

One-Sentence Definition

Breaking free from the limitations of linear causal reasoning, recognizing that many relationships in reality are nonlinear.

Core Concept

Nonlinear thinking recognizes that the relationship between input and output is not simply proportional. Small changes can lead to huge results (the butterfly effect), while large investments may have minimal impact.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps shift your judgment from intuition to structured analysis.

North Star Metric

One-Sentence Definition

A core metric that aligns the team by representing user value and business growth.

What Problem Does It Solve

It helps you break down growth into observable, diagnosable, and optimizable stages.

More specifically, the North Star Metric is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, which path, and which constraint should I look at first?

Nudge

One-Sentence Definition

Make good choices easier by designing defaults, order, and environment.

What Problem Does It Solve

It helps you understand why people don’t always act rationally, and design better choice environments.

More specifically, Nudge is suited for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, which path, and which constraint should I look at first?

Occam’s Razor

One-Sentence Definition

Entities should not be multiplied without necessity—the simplest explanation is often the closest to the truth.

Core Concept

Occam’s Razor principle: Among all possible explanations, the simplest one is usually correct. Do not multiply entities without necessity.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps pull your judgment back from intuition to structured analysis.

OODA Loop

One-Sentence Definition

Observe, Orient, Decide, Act, and iterate faster than the environment.

What Problem Does It Solve

It helps you turn ambiguous problems into clearer judgments, actions, and verification methods.

More specifically, the OODA Loop is suitable for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, which path, or which constraint should I look at first?

Opportunity Cost

One-Sentence Definition

The true cost of choosing one option is the best alternative you give up.

Core Concept

When faced with multiple choices, the highest-value option you forgo is your opportunity cost. Opportunity cost = Explicit cost + Implicit cost.

What Problem Does It Solve

When information is incomplete, options are numerous, or risks are unclear, it helps pull your judgment from intuition back to structured analysis.

More specifically, opportunity cost is suited for answering questions like: Is what I’m seeing a fact, an assumption, or a habitual practice? To make a better choice, which variable, path, or constraint should I look at first?