The term is essentially equivalent to “human-computer interaction”, except that it is used more often to refer to hardware, while HCI is used most often to refer to software.

Some special issues in healthcare include safety and cleanliness of physical devices, necessary knowledge of the medical domain and terminology, consistency of data representations, very high reliability, and privacy of patient data.

It’s often assumed that GUI applications are inherently more usable than text interfaces, but that may not be true when GUI applications are not well-designed. Graphics enable more flexibility in design and enable certain useful interaction styles (like direct manipulation), but text-based applications may still be extremely usable if they are designed through a user-centered process: gathering information from users, carefully designing the interaction tasks, conducting user testing, etc.

Three approaches to internationalization are common:

• globalization: making a monolingual interface more accessible for non-native speakers and international use. For instance, to make a website more accessible, use straightforward language avoiding jargon, make sure phone numbers include international country codes, and convert measurements to international units.
• multi-lingual interfaces: allow users to choose a translation into their own language.
• localization: customize the user interface for each local region in which it will be used, by using the local language and taking advantage of local conventions, assumptions, and common defaults.

MVC is generally implemented with callbacks – the underlying application registers with user interface widgets (in the view and controller) and gets called back by them when something changes in the interface that it must respond to. Complete separation of the model, view, and controller is not in principle entirely possible, since all of them must still contain code to communicate changes to each other. Similar in spirit to a later architecture known as abstraction-link-view (ALV).

Variations include a MOO (object-oriented MUD), MUCK (multi-user chat kingdom), and MUSH (multi-user shared hallucination). While some people make careful distinctions, the terms are used fairly interchangeably.

As an example, consider an application for choosing baby names where you want people to be able to find an appropriate name as quickly as possible. You would ask potential users (expecting parents, for instance) to rate the similarities of large numbers of names, e.g. “On a scale of 1 (very similar) to 7 (very dissimilar), how would you rate the names John and Sarah?” After getting a large number of ratings, the MDS algorithm would then determine the dimensions that best describe the data. The algorithm won’t name those dimensions for you, but will simply specify a number of dimensions and where each name falls along each dimension. So for instance, you may find a dimension in which Joe, Bob, and Tom all fall at one end while Jenny, Amy, and Susan all fall at the other end. In this case, you would be likely to identify the dimension as gender. In the example of names, you might also find dimensions of nationality and pronunciation. Thus, your interface for selecting names may allow the users to select gender, nationality, and sounds to help them find an appropriate name, or you may allow the user to ask for “similar” names once they have found one they basically like.