triz-intermediary

name: triz-intermediary description: Use an intermediary object, person, or process to connect two elements that cannot or should not interact directly

TRIZ Intermediary (Principle #24)

Overview

Intermediary is one of Genrich Altshuller's 40 Inventive Principles from TRIZ (Theory of Inventive Problem Solving), derived from analysis of over 200,000 patents. The principle states: use an intermediary carrier article or intermediary process to enable, improve, or protect the interaction between two elements.

The core insight: when direct interaction is impossible, inefficient, or harmful, introduce a third element to mediate the relationship. The intermediary can transform, translate, buffer, or optimize the connection without requiring changes to the original elements.

Intermediary appears in three forms:

1. Physical Intermediary - An object that enables physical connection (adapters, couplers, buffers)
2. Process Intermediary - An agent or service that facilitates interaction (brokers, translators, routers)
3. Temporal Intermediary - A mechanism that manages timing mismatches (queues, caches, schedulers)

When to Use

• Two elements cannot connect directly due to incompatibility
• Direct interaction would damage one or both elements
• The interaction needs translation, transformation, or buffering
• Modifying the original elements is impractical or expensive
• You need flexibility to change one element without affecting the other
• Distribution, aggregation, or routing is required
• Safety concerns prevent direct contact

The Process

Step 1: Identify the Direct Interaction Challenge

What prevents or degrades direct connection between the two elements?

Example: Vacuum cleaner motor generates high suction but cannot navigate tight spaces.

Step 2: Define Intermediary Requirements

What must the intermediary do to solve the interaction problem?

Requirements Categories:

• Physical Translation: Size, shape, material compatibility
• Property Transformation: Voltage conversion, speed reduction, pressure regulation
• Routing/Distribution: One-to-many, many-to-one, selective routing
• Protection: Shield from heat, chemicals, electrical discharge
• Temporal Buffering: Absorb timing mismatches, smooth bursts

Example: Intermediary must be flexible to navigate corners while maintaining suction.

Step 3: Design or Select the Intermediary

Choose the simplest intermediary that meets requirements.

Example: Flexible hose with internal ribbing for structural integrity.

Step 4: Optimize Interface Points

Ensure clean, efficient connection at both ends of the intermediary.

Example: Standardized coupling at motor end, swivel joint at attachment end.

Step 5: Test End-to-End Performance

Verify that the intermediary enables the desired interaction without introducing new problems.

Example: Measure suction loss through hose, test durability under repeated flexing.

Example Application

Situation (Software Onboarding Complexity): New users struggle with complex software setup, leading to high abandonment rates.

Application:

1. Direct Challenge: New user lacks knowledge to configure 30+ settings correctly
2. Intermediary Requirements: Guide user through decisions without overwhelming them
3. Intermediary Design: Step-by-step onboarding wizard with contextual help
4. Interface Optimization:
   • Start screen with single "Get Started" button
   • Completion screen with "Launch Application" transition
5. Testing: A/B test shows wizard reduces abandonment from 40% to 12%

Outcome: 70% reduction in support tickets during first week, 28% increase in successful onboarding completions.

Anti-Patterns

• Adding intermediary when direct connection is actually possible
• Choosing an intermediary that is more complex than the problem
• Creating bottlenecks through slow or limited-capacity intermediaries
• Failing to maintain or upgrade the intermediary as needs evolve
• Over-relying on intermediaries instead of fixing underlying incompatibilities
• Introducing intermediaries that add latency or reduce quality unacceptably
• Not providing fallback when intermediary fails

Related

• adapter-pattern (software design pattern for interface compatibility)
• proxy-pattern (intermediary object controlling access to another)
• mediator-pattern (centralized coordination between multiple elements)
• translation-layer (transform data/protocols between systems)
• buffer-abstraction (temporal intermediary for rate mismatches)