Human interface guidelines (HIG) are restrictions or specifications contained within a design document for the creation of hardware or software that indicate how the interface of these creations should be implemented. The HIG for a particular operating system (OS), for example, sets the standards by which the various windows, boxes, screens, and other features are designed. This is in reference not only to the aesthetic design of the user interface (UI), but also the interactive functions. Human interface guidelines can then be used by other developers working with such hardware or software to ensure proper compatibility and functionality in UI development.
Software development often includes a number of design documents used in the creation of a new program, including human interface guidelines. A company developing a new OS, for example, might create an HIG document that clearly indicates different colors used for different windows and messages, as well as icons for closing, opening, and otherwise interacting with boxes and features in the UI. This document can then be utilized within the company to ensure that human interface guidelines are followed, and that the final product has a UI that is clean, consistent, and useful.
The usefulness of human interface guidelines is key to their importance, as the HIG document is often created to ensure an effective user interface. UI developers often have an educational and professional background in understanding how people interact with different types of software and hardware. Input from a UI developer on the creation of HIG documents allows a new program or device to have a UI that is easy to understand and intuitive for new users. Though this may seem like a simple aspect of software design, flawed or incomplete human interface guidelines can result in a program that lacks consistency from one area to the next, or that is overly complex to use.
While human interface guidelines are important for internal use within a software developer or hardware manufacturer, they are often used outside of a company as well. A company that is developing new software to function with an existing OS, for example, might utilize the HIG document for that OS to ensure that the overall usability of the new software is in keeping with the features utilized in the UI of that OS. This ensures that multiple utilities and features that can run together, but come from different developers, remain cohesive in usefulness and present users with a single experience across a larger platform. In development of new software and applications available from a single software marketplace, for example those used by mobile devices, use of human interface guidelines can have a tremendous impact on the accessibility of software.