Disruptive Innovation (Christensen, 1997)

Overview

When to Use

• User asks why a startup with an inferior product is gaining market share
• User needs to evaluate whether a new entrant is a disruptive or sustaining threat
• User wants to design a market entry strategy targeting overserved customers
• User mentions "disruption", "low-end market", or "good enough product"

• For sustaining innovation management (incremental improvements) -> use stage-gate or innovation funnel
• For platform-based competition -> use grad-platform-economics
• For analyzing national-level innovation systems -> use grad-diamond

Assumptions

IRON LAW: Disruption Comes from BELOW

Disruption originates from the LOW END or NEW MARKET — never from a
superior product attacking head-on. Incumbents fail because they
OVER-SERVE mainstream customers, creating a performance overshoot that
opens space for simpler, cheaper alternatives.

If the entrant competes on the SAME performance dimensions as the
incumbent, it is sustaining innovation — NOT disruption.

• Performance trajectories improve faster than customer needs evolve
• Incumbents are rational — they chase higher margins upmarket
• Disrupted markets have identifiable overserved segments

Methodology

Step 1: Map Performance Trajectories

Step 2: Identify the Foothold

• Low-end foothold: Targets overserved customers with a cheaper, simpler, "good enough" product (e.g., discount airlines vs full-service carriers)
• New-market foothold: Targets non-consumers who previously could not access the product at all (e.g., personal computers vs mainframes)

Step 3: Assess Disruption Potential

1. Performance overshoot exists — mainstream customers do not use all features they pay for
2. Entrant has an upmarket migration path — the simpler product can improve over time
3. Incumbent has asymmetric motivation — responding means cannibalizing high-margin business

Step 4: Recommend Response Strategy

Output Format

# Disruption Assessment: {Industry/Company}

## Performance Trajectory Analysis
- Incumbent performance vector: {key dimensions}
- Customer need threshold: {what "good enough" looks like}
- Overshoot zone: {where incumbent exceeds needs}

## Entrant Classification
- Type: Low-end foothold / New-market foothold / Sustaining (NOT disruptive)
- Target segment: {who the entrant serves}
- Core advantage: {why target segment prefers entrant}

## Disruption Potential: High / Medium / Low
1. Performance overshoot: {Yes/No — evidence}
2. Upmarket path: {Yes/No — mechanism}
3. Asymmetric motivation: {Yes/No — why incumbent won't respond}

## Strategic Recommendations
- For incumbent: {specific response}
- For entrant: {next moves}

Gotchas

• Not every innovation is disruptive: Uber was NOT disruptive to taxis by Christensen's definition — it started in the high end. Label precisely.
• Disruption is a process, not an event: It unfolds over years or decades. A snapshot analysis misses trajectory dynamics.
• Incumbents CAN respond: Disruption is not inevitable. Autonomous business units (e.g., IBM PC division) can counter disruption.
• Technology alone is not disruption: The business model matters as much as the technology. A better mousetrap sold at higher prices is sustaining innovation.
• Beware hindsight bias: Many "disruption" narratives are retrofitted. Apply the framework prospectively with testable predictions.

References

• For mathematical formalization of performance trajectories, see

  references/performance-trajectory-model.md

• For case studies (steel minimills, disk drives), see

  references/disruption-cases.md