Feedback and Guidance assist the users to learn and use the system correctly and quickly.

Feedback:

i)Feedback to the user must be provided within a certain time limit so that it is useful and significant for the user.

ii) Excessive delays must be avoided since they cause:

• Lapse in concentration
• Increase in user anxiety
• Frustration
• Degraded Performance

a) Response Time:

The human thought process is very fast and the system response must be competitive with this speed so that the continuity is maintained.

b) Dealing with time delays:

• Button click acknowledgement:

All clicks made must be confirmed by some audible sound or visible indication within a split of a second so that the user is assured of performing the button click.

• Waits that require up to 10 seconds:

A delay that might take up to 10 seconds is quite conspicuous. Such delays must be acknowledged wih a busy indicator showing that the process is going on till it completes. E.g.the most commonly used animated hourglass cursor.

• Waits that require anything between 10 seconds to 1 minute:

Operations that require more than 10 seconds to complete, is a sizeable amount of time and must be indicate with larger animated objects.

A progress indicator can also be useful in showing the time left for completion or the time that has elasped.

• Waits that require over a minute:

When a wait is longer than a minute then estimate of the wait time must be provided.

Use progress indicators that also display percentage of completion of the operation, or elasped time along with the animated filling bar.

• Long, invisible operation:

When operations take long time to execute and progress indicators are not visible to the users then the acknowledgements can presented using a audible sound or by a message on the screen.

• Progress indicators:

This is an animated rectangular bar that is initially emptyand fills up corresponding to the progress of the operation.

• Percent complete message:

This is a message that presents the percentage of completion of operation or sometimes the percentage of operation that is left to be completed.

• Elasped time message:

It is similar to the progress indicator, but it is used for presenting only the amount of time elasped during the progress of an operation.

• Web page downloads:

Some web pages take ages to load. For pages that require download time exceeding 5 seconds, users must be provided with something so that they do some activity while they are waiting for their operation.

i)Provide with advertisements, offers, deals on the top of the page that is seen on the downloading screen.

ii) Inform users of the download time and also warn the user of the “Time Outs”.

• Blinking for Attention:

The attention of the user can be drawn or captivated by screen flickers or a flashing indicators towards those applications that are lying inactive and must be informed to the user.

i)For open windows te title bar can be flashed.

ii)For windows that are closed its icon can be flashed.

Guidance:

i) Errors can be categorized into slips and mistakes. A slip is an action that has gone off course automatically.

ii) Examples :

Wrong key being pressed due to fnger missing the intended key or accidentally press the adjacent key.

Incorrectly choosen menu item due to lapse in attention or carelessness.

Inference errors owing to negligence.

• Slips are easily noticeable and detectable as the wrong letter pressed will be visible on the screen or the desired action does not occur.
• They are often, but always rectified with ease.
• Proper application of human factors while designing the system would help reduce this type of error.e.g. key spacing on a keyboard or spacing between the choices on the list provided by the menu bar.
• When the users form wrong goals or assume improper models of their goals and then act on them, commits a mistake.
• They may not be easily detected since the output would not reflect a wrong goal that was initially assumed.
• Predicting a mistake in the design isn’t easy either. Mistakes can be reduced by:
• Keeping the design Unambiguous.
• Testing and monitoring usability.
• Detecting and correcting mistake prone situations.