Summary

Our goal to make the most efficient use of the user's time.

• Limit user decision making.
• Decrease data entry.
• Reduce machine manipulation.

Acknowledgements

This article is summarised from Bruce Tognazzini's site.

Simplify the Three User-Tasks

Users perform three tasks when using traditional machines.

1. They form judgements resulting in decisions relevant to the task being performed.
2. They gather the data necessary to perform the task.
3. They manipulate the machine by operating its controls.

User-performance is maximized by attacking each of the three steps: reducing the need for decision-making, enabling the machine to gather its own data, and cutting back on the amount of machine-manipulation necessary to achieve the goal.

Limit Decision Making

1. Do not use the user as a "rules database." Don't have users merely reporting decisions previously made and compiled into a book or binder.
2. Evaluate each remaining decision to ensure its necessity.
3. Provide the user with the information necessary to form decisions quickly and accurately.
4. Remove extraneous material.
5. Communicate through the visual design what are assumed to be the high-probability answers.

Decrease Data-entry

Two techniques can increase performance in data entry by minimizing the amount of information to be entered.

1. Pull up previous records and auto-fill as many fields as possible.
2. Minimize or eliminate data to be entered. Can the information be inferred? Is the information strictly necessary to perform the task? If not, is any secondary use valuable enough to offset the cost of entry?
3. Explore other means of obtaining the information.

Approach three, obtaining information by other means, is worth considerable effort. Make sure that you are looking at the "big picture". For example, one means of getting information off of paper forms and into the computer is to put the form through an optical character recognition system. Such systems are costly and, depending on the cleanliness and redundancy of the incoming information, may require more hand-work than they save.

Take a step back: Where are these paper forms coming from? Another machine? Consider how to eliminate the paper step entirely. Even if it can't be accomplished overnight, can it be in one year, two years, five years? What can you do now to begin a process that will result in enormous labor savings over that long haul?

Reduce Machine Manipulation

When analysing a design, constantly separate out those components of an operation that are machine-manipulation vs. the more abstract task of telling the machine something it otherwise couldn't know, either in the form of external data or user-judgments. Then:

1. Eliminate as much machine-manipulation as possible. Do this first on a gross level. Is this second screen necessary, or could this task be accomplished on one screen? Should the user really have to do this housekeeping task? Then perform the same review on a fine level. Is this keystroke/mouse click strictly necessary? Can this task be combined into a single step, rather than requiring two?
2. Make the remaining machine-manipulation track the user's model of the task. Avoid requiring users to make mental translations of the way they look at a task into a form your machine can understand. Offer instead the most direct and natural control possible. Don't perform this second task in a vacuum. The most direct and natural approach is dependent not only on the task, but on the profile of your users.