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Cognitive Accessibility Design Pattern: Design Forms to Prevent Mistakes

User Need

I need an interface that helps me avoid mistakes.

What to Do

Choose a form design that reduces the chance that the user will make a mistake. This includes:

  • Requiring the user to enter as little information as possible.
  • Clearly indicating required fields.
  • In a text field, accepting as many formats as possible. For example, accepting different formats of phone numbers.
  • Dividing long numbers into chunks (supporting autocomplete across fields).
  • Using an interface where only valid input can be selected.
  • Using autocomplete and personalization of form controls.
  • Accepting voice prompts when supported by the operating system.
  • Automatically correcting input errors when possible and reliable.
  • Providing the user with known suggestions and corrections.

How it Helps

After making many errors, people with cognitive and learning disabilities and users with age-related forgetfulness often abandon their tasks and believe they cannot complete them. Error messages may be confusing. Correcting errors is often difficult and frustrating for users and increases cognitive fatigue. Many users need to stop when they get successive errors.

For example, while registering for an online banking account a form requires the input of the user’s birthdate. The required input format is xx/xx/xxxx with a leading zero for single digits. If a single input field with no input correction is presented, a user with a cognitive disability may enter 1/3/1996 triggering an error notification. It may not be clear to the user that the required format is 01/03/1996 (even if the format is shown below the input field or in the error notification).

A well-designed form makes it easier to fill in the information and prevents the user from making mistakes by automatically correcting or suggesting the correct date format.

Minimizing user generated errors by automatically correcting them will also minimize error notifications. Error notifications may be tiring and distracting, taking focus away from tasks and task completion.

More Details

  • Clearly mark required content.
  • Only correct errors if the correction is reliable. Otherwise, if suggestions for corrections are known, give the suggestions to the user.
    • For example, “Did you mean the first of February (01/02) or the second of January (02/01)?”
  • Calendars and dates.
    • Calendars should default to the first relevant day. Work calendars should default to the first working day of a user’s locale.
    • Calendar-based booking systems must prevent the user from booking the return date before the departure date.
  • Temperature.
    • Use the default temperature format of the user’s location.



Designs that make mistakes less likely. For example:

  • Correcting errors of the post code being written in the text field with the city or state information.
  • Preventing the user from selecting inappropriate dates and providing a simple explanation if the user attempts to do so.


Designs that make mistakes more likely. For example:

  • The booking form provides two calendars without clear labels and instructions. The form allows the user to select dates without warning as to whether they are possible e.g. flight out on June 1st - flight return May 30th.
  • The system allows the user to select inappropriate dates without warning. The calendar merely grays out inappropriate dates which may not be noticed. No warnings are provided.

User Stories and Personas

User Story



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