People often confuse these three concepts and use them inadvertently for the same aspects of a website-related project.
In short: The information architecture (IA) defines the overarching structure and relationship between all areas of a site (or multiple sites) and informs the sitemap; the sitemap lists all the (labelled) pages in entirety and shows hierarchy, structure and often page goals and content/functionality that happens to be on that particular page; and finally, the navigation guides users via links to all areas of a website.
1. Information architecture (IA)
An information architecture is usually done at the initial phases of a project. Main goal is to organise and structure all relevant entities — preferably in a user-centric way.
Example 1: A retailer has websites for Australia and New Zealand, a blog, a community and a few social media channels. The AU website offers products/services for professionals and consumers, the NZ website only for consumers.
Example 2: A globally operating company employs a corporate intranet and several country intranets in multiple languages. Some content is produced centralised and shared with countries (e.g. news, jobs, events).
All of these entities can operate or exist individually, but it’s the job of the IA to show how they can/should interact with each other, how content can be shared and how people will navigate from one entity to the other, i.e. how the anticipated userflow will work.
Based on user and business needs, and backed up by research (e.g. card sorting exercises), the sitemap is created, challenged and enhanced. One starting point for the new sitemap can be the old one, enhanced with additional analytics data or business/user values.
The sitemap artefact usually lists all the pages that will exist within the new solution, ideally with assigned page goals and content/functionality that will be placed on the pages. In addition…