Week 2: Consistency

Everyone knows famous logo’s. Ford, Volvo, Apple, McDonald’s. Someone has to design them and they have to make them recognisable and easy. When people see the logo’s, they have a fair idea on what to expect because of past experiences. For example, I know I can expect a good car if I see Ford. I know to be careful if I am holding an Apple product. I know McDonald’s is fattening but tastes good. If the same logo is used on the same companies products, it is consistent and easy for the customers to know what to expect.

When signs and traffic lights are consistent, it makes it easier for people to know what to do. You know if you see a red octagon which has ‘Stop’ written in white on it, you should stop at the white light for three seconds at least. Obviously only start driving forward when it is safe to do so. When approaching a set of traffic lights and the light turns amber, you know to start slowing down, unless you are too close. Once the light is red, you know it is going to turn green soon. These are forms of functional consistency.

An alarm does not always have to have the same noise, but if you hear a loud noise, which sounds like an alarm, then you generally know something is wrong. It could be a fire alarm or a security alarm. These are forms of external consistency. They are consistent in the fact they are loud noises and they generally have someone, whether it is a prerecorded message or a real person, saying it is not a drill and that people are having to evacuate.

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Apple,. (2014). Retrieved from http://worldofdtcmarketing.com/will-apple-transform-mobile-health/mobile-healthcare-marketing-trends/attachment/apple-logo/

Challenge alarm services,. (2014). Retrieved from http://www.challengealarmservices.co.uk/

Ford,. (2014). Retrieved from http://www.ford.com.au/about/use-of-logo

McDonalds,. (2014). Retrieved from http://ilikewalls.com/mcdonalds-logo-4.html

Scooter Underground,. (2014). Retrieved from http://blog.scooterunderground.ca/general/traffic-lights-amber/


Week 2: Consistency

Part one. Summarise

People rely on consistency. It enables people to be able to efficiently transfer knowledge, learn new things quickly, and focus attention on similar tasks. There are four different types of consistency. Aesthetic consistency is a logo on a car or product. People look at the logo and know to expect good or bad things about it. Functional consistency is about actions. People know that when a traffic light goes amber, to expect it to go red. Or when a light goes red, they should expect it to turn green again, soon. Internal consistency is similar to other elements in the system, like signs in a park. External consistency is consistency relevant to the environment, like security/fire alarms. You must consider Aesthetic and functional consistency in all aspects of design.

According to Hassan, Sayed and Tabernero (2001), design consistency could be described as the way highway systems are designed to avoid traffic accidents. This could be functional consistency, since it is easier to use.

Consistency is also one of the most important aspects of design for interactive systems. It is quite often listed as encouraging to use. Almost every usability-expert will say consistency is important. Kellogg (1989), points out, “consistency has no meaning on its own; it is inheriently a relational concept. Therefore to merely say that an interface is consistent or that consistency is a goal of user interface design is also meaningless.” (Obendorf, 2009).


Hassan, Y., Sayed, T., & Tabernero, V. (2001). Establishing practical approach for design consistency evaluation. Journal Of Transportation Engineering, 127(4), 295–302.

Lidwell, W., Holden, K., & Butler, J. (2003). Aesthetic-Usability Effect. In Universal Principles of
Design (pp. 46). Massachusetts: Rockport.

Obendorf, H. (2009). Minimalism. Dordrecht [The Netherlands]: Springer.