Inline validation may seem useful at first insight, but should be implemented carefully and only if appropriate. If you’re still sceptical about its costs and benefits are, read on.
In this first article of the series I outweigh the pro’s and cons and provide existing researches and a checklist. In other of my posts you can read about the design and implementation challenges you might cross.
Inline validation is generally useful where users would expect it, like when filling in a username to see if it still available or a typing a new password to check if it is long and secure enough. If the system is not forgiving and is strict about format types, the user might start to wonder. Also, most users want to complete the form as fast but accurate as possible. If they click Submit and go to the next step, they might be less pleased to see the same form again (with errors communicated) and make the effort of correcting any errors (and waiting for the next step again).
What is inline validation?
Inline, real-time, or instant validation is a error communication strategy in electronic form design. A system responds immediately to an error, constantly validation user input and providing immediate feedback about input errors during filling out a form.
Two variants of inline validation exist:
a) On-the-fly: any error is communicated in real-time or instant, meaning as soon as the user has typed an invalid character in a textfield.
b) OnBlur: any error is communicated only after a user leaves a field by clicking outside it or clicking another field (a.k.a. loses focus). This is generally preferred method.
The opposite of inline validation is afterwards validation or on-submit (onSubmit) validation. That means that errors are communicated only after the user has clicked the submit button.
Just show me the numbers (or research)
Does inline validation increase conversion? When using inline validation on sign-up and ordering forms, do we really win more confidence from the users or only disturb them in their mental flow while filling the form? What about those green check-marks: do they really make filling in a check-out form more pleasant? Research about inline validation and its advantages for conversion is scarce and contradicting. There are no hard sales figures or proof of increased conversion, because research about inline validation is not conclusive about the link yet between different form types (sign-up form, order form or other) and design (content, error behaviour) in relation with its added value on different types of forms.
Research case A: inline validation didn’t help
One research paper covers ‘usable error messages on the web’  (not confirmed) that afterwards validation is more ‘effective’ than inline validation. I’m not sure what they mean by ‘effective’, but I deduct from the table of contents of the article that they define ‘effective’ by:
- lower error rates.
- lower time to complete.
- higher subjective ratings.
Summarizing their findings:
|When users are completing online forms present the errors after the user has completed the form.
– When completing an online form users have two flows or modes: Completion Mode and Revision Mode.
– Users tend to ignore immediate error messages when they are in Completion Mode.Of the six possible ways to present error messages, thee proved to be more effective (?) than the others:
o Present the errors afterward, embedded in the form, all at once.
o Present the errors afterwards, embedded in the form, one by one.
o Present the errors afterwards, in dialogues, one by one.Where presented with inline validation, users often simply ignored the messages on the screen and continued completing the form as if nothing happened. These results lead to the postulation of the “Modal Theory of Form Completion“: Users are in either “Completion“ or “Revision Mode“ when filling out online forms. These modes affect the users way of interaction with the system: during Completion Mode the users disposition to correct mistakes is reduced, therefore error messages are often ignored.
Interestingly most users don’t actually look at the inline validation unless they are worried their answers might be wrong. As soon as the user hesitates they look at the form and can see straight away whether their answer is right or not.
Research case B: inline validation helps
On the other hand, an article by Luke L in the aListApart.com article has opposite and positive findings on inline validation:
|The inline validation version had:
- a 22% increase in success rates,
- a 22% decrease in errors made,
- a 31% increase in satisfaction rating,
- a 42% decrease in completion times, and
- a 47% decrease in the number of eye fixations.
A discussion on ixda.org summarises:
“His research suggested that:
- validating data that shouldn’t be validated (e.g. first name, last name) was regarded as weird and confused users.
- speedy, immediate checking of data that should be validated (e.g. is my choice of username available?) is welcomed by users and helpful
- attempting to validate data before the user has finished typing is intrusive and disliked by users (a point we explore further in our book: it’s all about interrupting the user’s turn in the conversation). “
Inline validation can either harm or benefit your customer satisfaction and conversion. As every forms differs in content and design, so will each research differ in their findings. Not all design research is universally applicable; we should learn from the context rather than to generalise conclusions.
What does this mean for me?
A/B test inline validation on your site. Be weary about blindly applying something that gave positive conversion results on one site to another site – different sites have different audiences, even with time things may change. Conversion rate is an important monetary measure, but – just as the case studies above have done – measure other KPI’s as well: usability, customer satisfaction, aesthetic appeal and similar emotional factors should not suffer (too) much as a result of increased conversion. As always, mind the development costs, server load and performance decrease are feasible.
Read my related articles on inline validation:
Pros and cons of inline validation
Design and implementation challenges
When to use inline validation
Preparing for inline validation
Lies, damn lies and A/B tests
 Usable error message presentation in the World Wide Web: Do not show errors right away
by Javier A. Bargas-Avilaa, Glenn Oberholzerb, Peter Schmutza, Marco de Vitoa and Klaus Opwisa
Sign-up form examples:
Yahoo! mail sign-up page (UPDATE: Recently Yahoo has slightly redesigning their form and removed inline validation!)
Mint.com sign-up form
TypePad sign-up form (Last checked 5/5/11)
Audible.com sign-up (username onBlur, others onSubmit)
Order form examples:
Do you know of any e-commerce examples? Let us know.
A short chapter devoted to inline validation in Robert Hoekman Jr ‘s Designing the moment