I'm designing a reusable Wizard that will be used in multiple places of my web application. It is designed to be truly modular - we detect the number of stages and whether each has been completed by the user to show it's visual state.
The user can navigate backwards from stages they have completed via a Back link - a question remains - should the actual Wizard steps be clickable? Is there a best practice / rule around this?
Making the wizard links clickable for already completed sections is good for usability. While the number of times a user might actually have to return to an already completed section my be very low, at least having the ability to jump back to the beginning of that particular section might be useful.
While I don't have any particular best practices or references to any, I would at least indicate to the user the state of each section in the wizard no matter what part they are currently at. I.E. if the user return to part three but have completed up to part six, still show that part six is completed. Also indicate if they can move to part 7 or complete the wizard process might prove to be helpful.
Being able to access different steps of the wizard can be quite useful, especially if you have steps with some forms. Even though it's not the best of examples, here's one:
Unfortunately it's not in English but it's basically a shipping form for a product. It says "Customer Information", "Address Information", etc. In this wizard you can basically jump on any of the steps by clicking on them. But I don't think this is complete. There's really no indication that you can actually click on them for example because it's greyed out.
Another thing that is missing, related to your question, is that there could be information on whether if all the information is filled. This could be like a green "Completed" text with a check beside it for completing all information required, something orange with a question mark indicating that not all the optional forms has been filled and last but not least a "Incomplete" with a red cross.
This could work well with a wizard that would allow the user to actually skip ahead and checkout all of the form instead of a wizard that requires the information to be filled before getting on to the next step. With a wizard like that you could just make it so that the user would go back to the first step with missing info.
I concur that clickable step links "in general" offer good usability. But the purpose of the wizard really dictates the value.
JeffH says in his answer that the number of users that need it may be low. That depends entirely on the task that the wizard letss the user perform. If choices in a latter step prompt a user to reconsider their choices in a previous step, clicking the tab is essential to a good experience.
Since you are building a reusable wizard you should definitely build that functionality into your wizard generator. Consider a setting to turn it on or off
Here is an example of where going back to a previous tab is meaningful: https://www.sl.advertising.com/admin/ux/placementSelection.do?encqs=sTJQ%2Fz8I9iqtqg%3D%3D&plid=0
Placements, bidding and create ad can be returned to over and over even though they are completed while the user develops an ad campaign.
