Human Factors
Design Strategies

Copyright 1996
Richard Halstead-Nussloch
All Rights Reserved

7/9/96

Three Design Strategies
Statistically Distributed Features

• Design for the extremes of the range

Design for the extremes

• A design to include both extremes of the range
• Most inclusive
• Should be the first strategy tried
• Example: Height of doors

Three Design Strategies
Statistically Distributed Features

• Design for the extremes of the range
• Design for the adjustable range

Design for the adjustable range

• A design that allows adjustability throughout the range of the feature
• The degree of inclusion is determined by the range of adjustment
• Is generally more expensive than designing to include the extremes
• Example: Car seats

Three Design Strategies
Statistically Distributed Features

• Design for the extremes of the range
• Design for the adjustable range
• Design for the average

Design for the average

• A design that fixes on a value, hopefully near the average or central tendency
• The degree of inclusion is determined by
  • the spread of the distribution
  • the range of tolerance
• Is generally less effective and inclusive than either designing to include the extremes, or designing for the adjustable range
• Example: Counter top height

Three Design Strategies
Statistically Distributed Features

• Design for the extremes of the range
• Design for the adjustable range
• Design for the average