Why Users Fill Out Less If You Mark Required Fields

by on 04/15/14 at 11:58 am

Are most of your users skipping the optional fields on your form? You might not need that extra information, but having it could help you learn more about users and give them a better experience. If you want more users to fill out the optional fields on your form, avoid marking required fields and mark optional ones only.

Why Users Fill Out Less If You Mark Required Fields

Research shows that most users approach forms with “voluntary over-disclosure” behavior. This means that they regularly offer more information than required even when they’re told that doing so is voluntary. This contradicts the traditional assumption that users approach forms with the intent to complete as few fields as possible. However, when you mark a form’s required fields, it jeopardizes voluntary over-disclosure and makes users skip optional fields.

Marking required fields enable users to do the bare minimum to complete your form. They’re going to put more importance on required fields and fill those out first while ignoring the optional ones. Why would they spend time on optional fields if they can fill out what’s required and move on? However, if you use voluntary over-disclosure to your advantage and mark optional fields only, users won’t feel the need to take shortcuts. They’ll fill out each field in a linear progression instead of scanning for required field markers. Optional fields will then get the attention they deserve.

Thinking users won’t fill out a field unless you mark it as required is wrong. Users’ default behavior is to give more information than requested on forms. Users won’t pay attention to optional fields if you mark required ones because it makes them want to fill out less. Stop marking required form fields. This includes marking them with asterisks. Then maybe this outdated practice perpetuated by bad forms can finally end.


Why Users Fill Out Less If You Mark Required Fields Why Users Fill Out Less If You Mark Required Fields

Author and editor-in-chief of UX Movement. Loves great web experiences and fights for the user.

24 Responses to “Why Users Fill Out Less If You Mark Required Fields”

  1. Andrew Wirtanen

    Apr 15th, 2014

    I applaud Anthony and the cited article’s authors (Preibusch et al) for thinking outside-the-box and challenging assumptions.

    However, I disagree with the practice of not marking required fields for a few reasons. (1) Users are more likely to get errors – we should prevent errors, not design a form that encourages them. (2) We should not trick users into filling in more than necessary. This seems like exploiting our natural tendencies rather than protecting our best interests. (3) Screen readers will not be able to detect when a field is required unless there is additional hidden code. (4) Many users are privacy-minded and will likely react negatively to it.

    Jarrett and Gaffney (Forms That Work, 2009) recommend marking required fields with an asterisk and labeling the optional fields, since that is the convention that most web forms follow. They state that indicating only optional fields is “unusual, and therefore confusing”. Additionally (in line with Preibusch et al’s recommendation), I would tell users why we are asking for information if it is not obvious.

    • Ricardo Zea

      Apr 20th, 2014

      Interesting points Andrew, however:

      1]. I think is not about about what users are more likely to do (errors or successes), but build a form prepared to deal with errors. If you have solid client and server-side validations, you/we did our part in respecting the user experience. I don’t think not labeling required fields encourages errors at all.

      2]. “Trick”? Why would optional fields is “tricking” the users? If you’re not labeling your fields as optional (or required as it’s been done for so many years), you ARE tricking your users. I don’t think labeling optional fields is tricking the users in any way.

      3]. Not sure what you mean about “hidden code”. The easiest way to make a form field required is to put the ‘required’ attribute in it, like this: <input type=”email” required>. How’s that “hidden code”? Screen readers can perfectly read all the attributes of a form field like that. BTW, HTML is not code, is markup.

      4]. Maybe, but some might be totally Ok with it too.

      The convention of using an asterisk (*) to denote a field is required was very likely simply the only thing web developers back then could think of, they had no idea of user experience, usability, conversion or testing, nothing. And because back then only web developers/back end programmers were the only ones that dealt with web forms, the use of an asterisk became widely used but flawed practice to denote required fields.

      Same thing happened with tables, until Web Designers stepped in to set things straight. But it’s going to be a very long time before it happens with forms because they still need some sort of intervention from web developers, and in my years of experience I have met only a few, VERY few developers that are concerned about user experience.

      • James

        Apr 23rd, 2014

        There are arguments in favour of both approaches, indicating required or optional fields. I have to take issue with how you’ve responded to Andrew, though.

        1) “solid client/server side validation” does not in and of itself have anything to do with user experience, rather it’s the interaction design that achieves this – or not. Validation only detects errors and that’s client and/or server side scripting. The interaction design piece is what you do with the error detection, or more explicitly how you inform the user there are errors and, more importantly, how you get the user to correct them.

        2) IMHO, whether you label optional or required fields should be determined, in part, by what kind/complexity of form you have, how much of it is required and its purpose. A three field form with all fields required can be handled easily by no field specific indication. A multi-part form with 20 required fields vs 5 optional is a different beast. There is no absolute answer to this. If you think there is, I’d suggest you’re not looking at the form’s design context enough. All this research really says if you read the original piece, is that users will volunteer more information when fields aren’t labelled required. That may be a good or bad thing, again dependent on circumstances.

        3) First, markup most definitely can be referred to as ‘code’ particularly as it was originally derived from SGML and that was originally viewed as ‘code’. Besides in the case of a web browser, HTML is needed by a browser to determine how to render it … Or, put another way, to decode it.

        While a form field ‘required’ attribute may work for validation purposes and possibly screen readers, it’s not likely to play into the psychology of users volunteering more data. While this is certainly an accessibility issue, it’s not terribly germane to the crux of this piece of research.

        4) I think the privacy concern is very valid and suggesting “some may be OK with it” is hardly a solid ux design argument.

        • Andrew Wirtanen

          Apr 25th, 2014

          Good discussion, Ricardo, James :-)

          1) My original point was that many users have a mental model of how forms work, and not labeling required fields would break that. We should help prevent errors before the user hits the submit button, but that may not be possible if users skip over fields and hit submit.

          Not labeling required fields seems like we’re possibly risking wasting the user’s time. Users don’t want to spend time figuring out how a form works.

          2) I like James’ response to this. There is an ethical issue with not labeling required fields. The research shows that users will fill out more if fields aren’t marked required. So, if we want users to fill out more info, then we should not label required fields. But, do we need to collect that extra info? Do we need to possibly waste the users time?

          3) I wasn’t familiar with the required attribute that was added in HTML5. If “required” is read out to screen reader users, then they may not have an issue. However, screen reader users would likely be more accustomed to the label containing “(required)” or an asterisk.

          4) Agree with James. Also, the asterisk is a de facto standard that may not be easy to change. The asterisk likely evolved from footnotes in text as pointed out on StackExchange: http://ux.stackexchange.com/questions/10468/why-does-asterisk-mean-required-on-a-form-field

      • Taelor

        Apr 28th, 2014

        Agree completely.

  2. Nathaniel Rink

    Apr 16th, 2014

    Do you have thoughts on forms where all fields are mandatory?
    I feel like it’s implied and that adding asterisks and “required” instructions clutter the form, ruin spacing, and set up a confrontational tone between the website and the visitor and that leaving the form clean and blank takes advantage of your voluntary over-disclosure instinct.

    Coworkers believe that the lack of instructions means users have to spend cognitive effort inferring that all forms are mandatory.

    Do you have thoughts or research?

    • anthony

      Apr 20th, 2014

      The only time a user will question if a field is mandatory is when they feel the information you’re asking for isn’t necessary to accomplish their task. For example, asking for phone number or home address in a sign up form. If you’re asking for sensitive information you should put a help tip next to the field label so that users know why you’re asking for it and what you’ll use it for.

  3. Chris Ota

    Apr 16th, 2014

    Great tip to point out. It might be better to separate all optional fields below the required fields, but I guess that would depend on the sequence of the form.

  4. Shawn Rubel

    Apr 17th, 2014

    I like this approach, I wish I had thought of it long before I did, and it makes perfect sense. I’m always skipping some of the fields on forms where those that are required to be filled out are emphasized. It’s only a matter of time before we get asked the names of our pets, etc,.

    Thanks, hadn’t seen this research paper before!

  5. Steve Peck

    Apr 17th, 2014

    What a dead simple, but incredibly smart insight. Appreciate you sharing. We have not yet put this ‘optional’ strategy to work (but will) however do keep our initial gates as minimal as possible, while then collecting what many consider the ‘optional’ information from right within the downloadable content.

    By doing this, we’ve actually scene that once engaged, users are much more likely to provide follow up information compared to having to provide multiple fields within the initial gate.

    Keep the good tips coming!

  6. Ecommerce

    Apr 18th, 2014

    Nice article. Forms and getting required information is one of my biggest weaknesses. I want to know everything, but at the same time I don’t want them to abandon either.

  7. Gene Eugenio

    Apr 20th, 2014

    It is very intimidating to see REQUIRED FIELD everywhere.The less intimidation, the more signups. The key is to sign as many people up as possible. Let the list sort them.

  8. Ricardo Zea

    Apr 20th, 2014

    This article just rox. It hits the problem right on the head.

    I’ve personally dropped labeling required fields altogether years ago whenever I have the power to influence the creation of a web form.

    Time to share this thing :)

    Thanks!

  9. Pradeep Kumar

    Apr 21st, 2014

    It is human psychology, if you make mandatory to fill some fields then optional fields will not be filled, if there is no rule then all fields are filled. Nice research. It will help some webmasters.

  10. Phil Ohren

    Apr 22nd, 2014

    Fantastic research by Preibusch.de – incredibly detailed. Such a simple thing we’ve overlooked for some time.

  11. ukash

    Apr 22nd, 2014

    Great tip to point out. It might be better to separate all optional fields below the required fields, but I guess that would depend on the sequence of the form.

    It is very intimidating to see REQUIRED FIELD everywhere. The less intimidation, the more signups. The key is to sign as many people up as possible. Let the list sort them.

  12. Norik Davtian

    Apr 26th, 2014

    This was a very interesting study. I love this quote from the study: “[Forms] are the metaphor for the explicit invasion of privacy.”

    Also, highly recommend everyone to read the limitations section of the paper before taking the findings as a concrete fact.

    Thanks for sharing.

  13. W3Responsive

    Apr 30th, 2014

    Your post give me idea how can i improve my development while creating form, i never think in that way. Thanks Anthony

  14. Lauren

    May 2nd, 2014

    How does this approach stack up to 508 compliancy? I believe spec explicitly says for fields to be labeled “required”.

  15. Robert

    May 8th, 2014

    I do not know why is that so, but required fields have some purpose there and you can not have optional field where you enter e-mail address for sending e-mails.

  16. Tim

    May 20th, 2014

    This is a very interesting discovery. As someone who fills out tons of stuff online I can say I always just enter the minimum amount and skip the optional fields.

  17. eeklipzz

    Jun 11th, 2014

    I absolutely LOVE this. Thanks so much for sharing.

    So then, if there are required fields, you only tell the user when they go to submit that they must enter the specified fields out to continue? I think there would be a nave for this…

    Dark Pattern.

  18. Ellen

    Jun 12th, 2014

    Great article.

    There’s plenty of UX research for retail sites, but has anyone considered this in the context of a more complicated software application? We can assume users have some level of familiarity with the checkout process when purchasing something online, but not necessarily for a form/process the world of SaaS. I would be interested to get thoughts on this aspect of UX design.

    However, I would guess that the psychological inclination to provide more information would most likely transcend the context of the form.

  19. Rob

    Jun 23rd, 2014

    The “problem”, IMO, stems much due in fact that forms have become excessive and full of both non-essential and needed information for many sites. So we leave it to the user to have to filter or read “needed” vs “optional” and decide what they want to fill in or not. These approaches address how to make that “decision” easier, but still fundamentally leave the user to be more mentally engaged with the form than they need to be.

    The truly easiest, user-friendly way to approach this, IMO, is to only feature essentially needed information on the form, unless it’s a marketing survey or other:

    This is what we need. Please fill it out.

    If you want to add a couple of non-essential questions here and there, ok fine. Label it optional but don’t break the model of “please fill all of this out”. You don’t see optional fields on credit card applications, job applications, and medical forms.

    Have life-threatening allergies? (optional)

    ________________________________________

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