People describe different types of UX such as Agile UX and Lean UX. Looking at the Agile manifesto and Lean methodology, it would seem to me that a successful implementation of UX processes would require a flexible and efficient process anyway. Is the use of Agile or Lean UX redundant or does it mean something more that I am not aware of?
Lean or Agile are only methodologies of applying a discipline, be it software development or UX design.
The arrangement between the UX specialist and the dev team (external consultant, internal full time, etc...) determines heavily what methodology would be used. E.g., if you're not an integral part of the development organization, then Lean UX can be tough, if not impossible (correct me if I'm wrong on this assertion).
Another factor influencing the UX methodology is the the one used by the dev team itself. You'd be surprised to hear that there are still organizations that work in a Waterfall style (though they might not admit it). If they do, they expect a fully detailed UI specification before they begin their work, something not imaginable by the Lean or Agile methodologies.
In my experience agile development can be antagonistic towards UX, especially if UX is attempted to be made to fit within an agile development frame work. The issues with agile don't relate to how successful then can be for development teams but when either UX concepting is attempted within sprints or if key design is done on the fly with the development driving the design. Agile is great for developers and UX, in my experience, works best when it feeds that development process with the right level of specification for what is being built.
And that is where Lean UX comes in. From my understanding (and different people understand it differently), Lean UX is all about reducing the amount of deliverables and attempting to create what is needed to concept, communicate, test and develop the final UX. What is 'right' differs between projects and, most importantly, between the team you have. No one process is right for all teams and all projects and it is the team that, ultimately, makes the project work or fail, not the process.
Lean UX also taps into an old idea of trying to make designers view all team members as collaborators on the design. A good development team will work well with their UX resource and a good UX team/person will ensure that developers are involved with the design process. Having said that the important part is that the UX effort is respected and that the developers are given the permission to focus on engineering and implementation and are not responsible for design or functionality.
Lean UX works best when a production line is working where UX solutions are delivered to the developers when they needed but the developers only have the responsibility of saying when UX solutions are not feasible.
So, in summary, Lean UX, if done well, is a great complimentary approach that fits in well with an Agile development team, but it's not really the same thing.
Also Lean UX is not the same as Lean Start up as it does not have to build then test but can spend time researching how users use thing, providing it's done in a light way, for example two weeks spent interviewing staff members about an intranet is great whilst a two month research process is not Lean.
This all depends on what your definition of UX is... which has been a changing beast over the years - from what the experiences is through to a job description for certain kinds of role.
I would personally say that you do need the qualifiers - since you can apply UX practices in many different contexts. For example:
Now - I have my opinions about which of the above three approaches are more likely to get you a great product - but I certainly think it reasonable to be able to label them differently. There are certainly more or less suitable UX design approaches depending on the domain.
Personally I think that it's expressing the maturity of the UX domain that we're having these sorts of UX process discussions now - and realising that there isn't one-true-way of doing UX work.
Although I am a staunch supporter of agile and lean methodologies in UX, it's important to remember that they are just methodologies. UX is not about how you create a great user experience, rather it is about what the user experience is.
So there are many different UX methodologies that can achieve good results. Often one methodology is more suited to a situation than another, so sometimes (given constraints) lean / agile methodologies aren't the best choice for a situation.