Quantitative measures of effectiveness
Speed
The speed at which an interface interacts with the user is fundamental to its effectiveness. If it reacts very slowly to a user then it is likely to be ineffective. Speed can be measured as:
• How quickly the user can input a command
• The speed at which a user can type in any data
• The speed of throughput, or the response given by the interface
• The length of time necessary for the user to comprehend the result.
With throughput, the response given by the interface needs to be quick and beneficial in order to be seen as effective. An example would be if the interface were to time out if the reaction from the user was too slow, this could determine effectiveness. The time needed for a user to understand the result presented by the interface could be used to measure speed and in turn effectiveness.
Comparative costs
Effectiveness of a HCI can be measured by its running costs in comparison to what may have been used beforehand. If an interface holds a large number of images or relies on other programs to support, then it likely to cost more to power it. Consideration must also be given towards additional staffing costs to use or maintain the interface.
Comparison with original needs
The effectiveness of a HCI can be measured quantitatively by comparing the final product provided and the original needs given by the user. You must find out how closely the product matches the original design or the requirements of the client by asking questions like:
• How many features are fully included?
• How many are partially included?
• How many features are not included?
• How closely does it meet the needs of the client/user?
It is also important to compare the HCI with other similar systems in order to provide ideas for future improvements. However, these comparisons must always be made as fair as possible by being realistic. If the system that your interface