Can user experience design (UXD) and user centered design (UCD) be considered the same?
If not, how do they relate to each other and how do they differ?
Put another way, user-centred design is a method (or process) to achieving good user experience.
Here is an example UCD design flow using SAP (note arrows indicating a process):
Source: SAP Design Guild
UXD describes what's designed (the experience). UCD describes the process (starting with user research and validated through artefacts like personas). In practice, most UX designers try to work in a user-centered way, but that's not always easy to achieve under commercial constraints, especially when the user and the customer are not actually the same person (e.g. advertising products).
First define UXD and UCD ;-)
And since, in my experience, if you get four UX folk in a room you'll end up with eight different definitions it's hard to give an answer that will please everybody.
I've seen definitions that would make them roughly equivalent.
I've seen UXD described as a generic umbrella term, with UCD being a specific instance of a process for doing UCD.
I've seen UXD described very narrowly, with it fitting in as part of a broader UCD process.
Swings. Roundabouts. Roundabouts. Swings.
My answer from the gut would be "It doesn't matter." Pick any definition you like. The particular names we pick don't help us build better products.
I found an article today on A List Apart where the author describes it in this way:
The terms “user experience design” (UX) and “user-centered design” (UCD) are often used interchangeably. But there’s an important distinction.
UX design is the discipline: what we do.
User-centered design is a process: how we do it.
I agree with him.
UCD is a part of User Experience designing. The experience for the user is not valid if the user has not been kept in mind. The UCD approach does just that.
I think it's important to distinguish between UX-design and UX first, because UX only describes the term. (Like usability does.) UX-design is more about how to achieve good UX.
In my opinion UCD tries also to establish good UX by focusing on the user. Therefore the terms UXD and UCD are quite similar. UCD is also seen as a process, so that one could say it's a (more) concrete instance, whereas UXD is a field.
Thinking in an evolutionary way I would say that in these days UX-design is a kind of successor of UCD which itself has evolved out of usability engineering. (Usability Engineering -> UCD -> UXD)
From my understanding (and this does seem to be a subjective issue) UCD is all about designing purely for the users' needs so that they can achieve what ever it is that they want/need to. Whereas UXD is all about crafting the join between user and business.
If an online bookshop used purely UCD techniques, you would go there, easily find the book that you want, be shown the simplest selection available, buy the book and leave. A very streamlined process for the user but this doesn't meet the business needs - i.e. 'sell more books'.
With UXD, you are trying to find the best way for the user to experience the business.
To reuse the bookshop analogy: You go there, see lots of books that might be of interest based on your previous purchases or searches, request the book you want, be shown a variety of editions with different binding at different prices along with a variety of related titles, purchase your book and anything else you may have chosen, receive an email a couple of weeks later asking if you were satisfied and inviting you back to the site to leave a review where you will also have the opportunity to by further books based on your now extended purchase/search history. Not so streamlined in terms of making your purchase, leaving and then firgetting about it all but hopefully an experience that will encourage you to revisit the bookshop or even tell your friends about it.