Portrait of Edd Dumbill, taken by Giles Turnbull

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What I make

a conference management web application

XTech Conference
a European web technology conference

Collecting minimal user information

Web applications are in constant competition for a user's attention. Unlike shrink-wrap software, there's often no captive audience, and web apps must gently guide and woo users to help them to the best experience of the software.

This is particularly true when considering the problem of collecting personal details from a user. Collect too little information, and your app might not be able to function effectively. Collect too much information, and you raise the barrier for participation with your application. Users may either not be bothered, be alarmed at the apparent intrusion into their privacy, or fill out bogus information. 

One size doesn't fit all

I originally stumbled on the issue in the development of Expectnation. The amount of information a conference speaker needs to give the organizers is significantly more than that of, say, a reviewer. An organizer will often want postal and phone details for a speaker, which are largely irrelevant to the review process. All conferences and events rely on the willingess of participants, so the path to participation needs to be as frictionless as possible.

Thus, a one-size-fits-all personal details form didn't make sense for us. At best, we could have simply made more fields optional, but that would result in missing information that we really did need.

Another solution would be to provide a dedicated personal details form per user type, e.g. different forms for speakers and reviewers. This is a non-starter, however, as users can take on many roles within a conference.

So, we had a problem on our hands: different levels of interaction with our application requires different levels of personal information.

We also had a second problem, which is that not all events and organizers want the same level of information. For example, a user group event is unlikely to need the same amount of information from speakers as an academic conference.

Thus we have two axes on which the amount of information required varies: by role, and by event. 

Our solution: progressive disclosure

We concluded that we wanted to adhere to two principles in the collection of user information for Expectnation:

  • collect as little information from users as possible, and
  • allow organizers to determine the level of information they wish to collect.
The first objective was achieved by constructing a matrix of information items against user role, with the possible values of {required, optional, unused} for each item. We then achieved the second objective by allowing this matrix to be varied over each event.

We've named this concept "progressive disclosure."

What this means in practice is that a user is only ever asked for the information required to fulfil the roles they have within Expectnation. If they take on another role, they are asked for the additional information at that point, and not before.

Implementation concerns

Expectnation user disclosure editing
Extract from disclosure level editing UI

It would be untrue to say that progressive disclosure is simple to implement.

A user in our system will have disclosure requirements that are the union of all of their roles in all of the events they attend. Within Ruby on Rails, this means the conventional validation logic is useless to us, as it only deals with static requirements. Secondly, disclosure requirements are expensive to compute, so we need to cache them, with the inevitable addition of issues such as cache invalidation.

Beyond the data model issues, the user interface issues are, if anything, more troublesome. From an end-user's point of view, the difficulty arises when we need extra information from them, and presenting this in a way that makes sense.

From the event organizer's point of view, we have the challenge of presenting a controlling user interface for rather a complex concept. Organizers must be able to change the level of required information either globally, or per-event.

We opted for a grid presentation, an extract from which is shown in the screenshot in this article. Over time we'll be able to see how effective this interface is, and what we can do to improve it.

Finally, we have chosen sensible defaults for all disclosure levels, as the best result would be that organizers have little need to reconfigure the settings in the first place.

Making it look easy

Because Expectnation is a general application for organizing events, rather than targetting one specific one, we've had to construct a framework for minimizing user information collection, as opposed to simple implementation of known scenarios.

At the end of the day we have added a fairly complicated subsystem and an extra degree of complexity to our codebase. However, the result from the user's point of view is increased simplicity and a streamlined experience.

Every time you embark on something that wide-reaching and complex, you have to ask yourself whether the feature is really worth it. In this case, though, the answer is a resounding "yes". The user is the most important factor in our software, and making their life easier in an unobtrusive manner is a priority.

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