Rules of Thumb -- Collected Heuristics Across All Chapters

Key Principle

Disruption theory is circumstance-based: the same action produces different outcomes depending on conditions. These rules of thumb encode the circumstance-detection logic from each chapter into quick-test principles organized by decision type. Each heuristic is a compressed version of a causal mechanism documented in the book -- not a universal best practice, but a diagnostic trigger that tells you which mechanism is likely active.

Why This Matters

Managers face dozens of innovation decisions before they have time to work through full theoretical frameworks. These heuristics serve as early-warning systems and first-pass filters. They do not replace the underlying theory -- a rule of thumb that fires should prompt deeper analysis using the relevant chapter's framework. But they dramatically reduce the odds of the most common and most expensive errors: investing in sustaining battles against incumbents, shaping disruptive ideas through sustaining processes, modularizing too early, hiring the wrong managers, and funding ventures with the wrong capital profile.

Good Examples

Sony's milkshake moment: Sony launched 12 disruptive growth businesses (1950-1982) under Morita's intuitive, observation-based approach to finding jobs-to-be-done. After MBA-trained marketers with quantitative attribute-based methods took over, Sony launched zero disruptive growth businesses for 18 years (Chapter 3). The heuristic: if your segmentation uses demographics rather than circumstances, you are likely missing the job.

Discount retailers vs. department stores: Discount retailers earned approximately 23% gross margins with 5x inventory turns (120% ROCII), matching full-service department stores at 40% margins with 3x turns. The business model itself was the asset -- as discounters moved up-market, much of the price increment fell directly to the bottom line (Chapter 2). The heuristic: if a competitor profits at prices you consider unattractive, they have a disruptive business model and will improve.

Intel's emergent strategy: Production schedulers allocated wafer capacity by gross margin per wafer start, shifting away from DRAMs even while senior management invested two-thirds of R&D in DRAMs. Management's deliberate strategy was DRAMs; the company's actual strategy was microprocessors (Chapter 8). The heuristic: to understand actual strategy, follow the money, not the memos.

Counterpoints

Oracle's $200 Internet appliance: Targeted households that had no computing job to do. No amount of price reduction creates a market where no job exists (Chapter 4). The heuristic fires incorrectly if you confuse "can't afford" with "doesn't need."

Prodigy's suppressed signals: Prodigy's fatal error was suppressing emergent signals (e-mail usage) as deviations from its deliberate online-shopping strategy (Chapter 8). Rules of thumb about strategy must be paired: be emergent early, but also recognize when to shift to deliberate mode once a viable strategy surfaces.

Western wireless data companies vs. NTT DoCoMo: Western companies modularized and partnered in an interdependent (not-good-enough) circumstance, producing massive losses. DoCoMo integrated and succeeded (Chapter 5). The modularization heuristic only applies when the product is more than good enough.

Key Quotes

"The acceptance of randomness in innovation is not a stepping-stone on the way to greater understanding; it is a barrier." -- Christensen & Raynor, Chapter 1

"Focus is scary -- until you realize that it only means turning your back on markets you could never have anyway." -- Christensen & Raynor, Chapter 3

"To understand companies' actual strategies, pay attention to what they do, rather than what they say." -- Christensen & Raynor, Chapter 8

"The things that people want to accomplish in their lives don't change quickly." -- Christensen & Raynor, Chapter 3

Rules of Thumb

Customer Selection

• If potential customers are currently nonconsumers whose reference point is nothing, you have a disruptive foothold. If they are happily served mainstream customers, you are in a sustaining battle. (Chapter 2, Chapter 4)
• Nonconsumption is only an opportunity when people are actually trying to get a job done but can't. If the job doesn't exist, neither does the market. (Chapter 4)
• If anyone on the team says "If we can just get the customer to...," the venture is pushing a product, not solving a job. Stop. (Epilogue)
• Frame disruption as a threat internally to secure resource commitment, then transfer responsibility to an autonomous unit that frames it as an opportunity. (Chapter 4)
• Half of early angioplasty patients suffered restenosis within a year, yet the market boomed -- because the alternative was no treatment. Imperfect solutions beat nonconsumption every time. (Chapter 4)

Product Design and Segmentation

• If your market segmentation uses demographics, product categories, or organizational boundaries rather than jobs-to-be-done, you are almost certainly averaging across distinct jobs and producing a product that does none of them well. (Chapter 3)
• The critical unit of analysis is the circumstance, not the customer. The same person may need completely different products at different times of day. (Chapter 3)
• If over 60% of your development efforts get scuttled before market and 40% of launches fail, you likely have a segmentation problem, not an execution problem. (Chapter 3)
• Purpose brands work because they tell customers which job the product was designed for. If your brand doesn't communicate a specific job, you are competing on attributes. (Chapter 3)
• Don't ask customers to change priorities. Products succeed by helping customers do existing jobs better, not by creating new needs. (Chapter 3)

Architecture and Scope

• Ask "Is the product not good enough?" If yes, integrate. If the product overshoots what customers need, modularize. Never use historical profitability to predict future strategic importance. (Chapter 5)
• Before outsourcing any component, test three conditions: Can both parties specify which attributes matter? Can they measure compliance? Are there no unpredictable interdependencies across the interface? If any answer is no, keep it in-house. (Chapter 5)
• "Core competence" is not a fixed attribute. What seems noncore today may become the critical proprietary capability tomorrow -- and vice versa. Run the RPV test, not the core-competence label. (Chapter 5)
• When modularity commoditizes one stage of the value chain, profit migrates to an adjacent stage that is becoming interdependent. Do not divest the stage where the money is going to stay where the money has been. (Chapter 6)
• Watch for the ROA-maximizing death spiral: each outsourcing step improves ROA but transfers future profit potential to suppliers. If you are outsourcing to improve financial ratios, check whether you are also outsourcing your ability to differentiate. (Chapter 6)

Organization and People

• A process that is a capability for one task is simultaneously a disability for a different task. Never assume that a team excellent at sustaining innovation can execute disruptive innovation. (Chapter 7)
• Evaluate managers by which problems they have wrestled with, not by innate attributes or track records at scale. Up to 40% of newly hired senior executives quit, underperform, or are fired within two years -- usually because of experience mismatch, not talent deficit. (Chapter 7)
• If you acquire a company for its processes and values, keep it independent and infuse your resources. If you acquired it for its resources, integrate it into the parent. Reversing this destroys what you paid for. (Chapter 7)
• An organization cannot disrupt itself. If a disruptive idea enters the normal innovation pipeline without executive sponsorship, assume it has been reshaped into a sustaining initiative. (Chapter 7, Chapter 10)
• The correct trigger for CEO involvement is not decision size but whether existing processes and values were designed for the decision. If not, the CEO must be involved. (Chapter 10)

Strategy Process

• Over 90% of successful new businesses pursued a strategy substantially different from founders' original plan. Demand emergent strategy early; shift to deliberate only after a viable strategy surfaces. (Chapter 8)
• The resource allocation process is the actual strategy. If you want to know a company's real strategy, follow its capital and headcount, not its strategy documents. (Chapter 8)
• Use discovery-driven planning: state required financials, rank assumptions by criticality, test the most critical assumptions quickly and cheaply, invest only after validation. Traditional planning produces "charade cycling" where assumptions get revised to make numbers work. (Chapter 8)
• Two strategy failure modes are equally fatal: (1) spending all resources implementing a deliberate strategy before viability is known, and (2) failing to shift to deliberate mode once a winning strategy emerges. (Chapter 8)

Capital and Growth

• Be patient for growth, impatient for profit. Impatience for profit forces learning (testing whether customers will pay, keeping costs low). Patience for growth permits competing against nonconsumption and following emergent strategy. (Chapter 9)
• If a new venture has been unprofitable for years, it has almost certainly been shaped into a sustaining competitor in an established market. Persistent losses are a diagnostic signal, not a sign of insufficient patience. (Chapter 9)
• Launch disruptive businesses in a predetermined rhythm while the core is healthy. If you wait until growth stalls, you will pressure new businesses to grow too big too fast. (Chapter 9, Chapter 10)
• Keep disruptive units small so that small opportunities remain attractive. A $1B unit needs $150M in new business; a $20B monolith needs $3B -- and will kill anything smaller. (Chapter 9)
• There is a ticking clock behind every new venture, and it ticks at a rate determined by the health of the corporate bottom line, not by whether the venture is on plan. Profitability is the best insurance against that clock. (Chapter 9)

Meta-Heuristic

• Disruption theory is predictive, not random. If you believe innovation success is a coin flip, you will design portfolio strategies that tolerate failure rather than initial-conditions strategies that prevent it. "The acceptance of randomness in innovation is not a stepping-stone on the way to greater understanding; it is a barrier." (Chapter 1)
• Disruption is relative, not absolute. The same technology can be sustaining to one company and disruptive to another. Always ask: disruptive to whom? (Chapter 2)
• The three litmus tests must be applied sequentially: (1) new-market test, (2) low-end test, (3) universal test -- is the innovation disruptive to all significant incumbents? If sustaining to even one major player, that player will likely win. (Chapter 2)

Related References

• The Role of Senior Executives in Leading New Growth - CEO involvement principles that enable organizational heuristics
• Implementation Playbook -- The 14 Executive Directives - The 14 directives as a sequential decision checklist