Minimize User Errors


3.3.3 Error Suggestion: If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content. (Level AA)


@@3.3.3 Minimize user errors: Input errors are automatically corrected where the correction is known to be reliable and achievable. Otherwise, @@if suggestions for corrections are known, the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content.



Alternative wording

Have a new SC : Input error are automatic correction where the correction is reliable.


Suggestion for Priority Level


Related Glossary additions or changes

common input error
errors that have been have been documented in the understanding of the Success Criteria section or have supportive techniques or that have been reported or documented more then one time and there is a know way to identify them
known to be reliable and achievable
Identified in the WCAG techniques as possible to reliably correct an errors, or found in user testing to constantly

What Principle and Guideline the SC falls within.

Principle 3 Understandable - Guideline 3.3: Help users avoid and correct mistakes.

This is an update to 3.3.3 Error Suggestion


The intent of this Success Criteria is to minimize user generated errors by detecting, and when reliable and possible, automatically correcting common input 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 thus triggering an error notification. It may not be clear to the user that the required format is 01/03/1996 even if an example for instance, xx/xx/xxxx, is shown below the input field or in the error notification. To alleviate any confusion for the user the application should insert a leading zero if a single digit is entered into the month or day along with the required forwardslash characters which act as a delimeter between the month, day and year.

Minimizing user generated errors by automatically correcting them will also minimize error notifications. Error notifications may be distracting for some users with cognitive disabilities, taking focus away from tasks and task completion. Users with cognitive disabilities may find it difficult to understand how to correct an error even when a notification is given. In the case of an unsuccessful form submission, this group of users may abandon forms because they are unsure of how to correct the error even though they are aware that an error has occurred.

If automatic correction is reliable and possible it should be implemented. If automatic correction is not possible the content author, the user agent or supported APIs should provide a description of the error along with suggestions for fixing the error except when to do so would jeopardize the security or purpose of the content.

This Success Criterion helps users who need help preventing errors.


People with cognitive disabilities and aging users abandon tasks and believe they cannot complete them if they receive too many errors. <See Neilson studies>

We need to minimize errors because:

  • Error notifications may be confusing for users with cognitive disabilities. Many users will not understand the problem making the task impossible to complete
  • Correcting errors is often difficult and frustrating for the user. Many users give up when they get successive errors
  • Error notifications can distract a user from tasks and task completion
  • Correcting errors before they occur will minimize the number of actions needed to complete a task or process

This Success Criterion helps people with many different cognitive disabilities including people with:

  • Language related disabilities
  • Memory related disabilities
  • Focus and attention related disabilities
  • Disabilities that effects executive function and decision making

Related Resources




Step 1. Identify data with a constrained format in the form

Step 2. look at techniques for these types of data formats to see if they are included as reliably fixable

Step 3. Input common formats for a field which has a data format requirement (as identified in the techniques)

Step 4. Confirm that all common formats for writing the information are accepted


  • Accept as many formats as possible of different ways of writing a phone number
  • Accept as many formats as possible of different ways of writing a date format
  • Using an interface were only valid dates can be selected
  • Accept voice prompts for people with a speech impairment
  • Correct errors of the post code being written in the text field with the city or state information
  • Calendars and dates
    • Calendars should default to the first relevant day. Work calendars should default to first working day of a user's locale.
    • Calendar based booking systems must avoid ability to book return date before departure date.

      Failure example: The booking form provides two calendars without clear labels and instruction and user is able to select dates without warning as to whether they are possible e.g. flight out on June 1st - flight return May 30th.

      Pass example:User is unable to select inappropriate dates and a simple explanation provided should he/she try to do so.

      Failure example: User can select inappropriate dates without warning. Calendar merely grays out inappropriate dates which may not be noticed. No warnings provided.

  • Temperature
    • Use the default temperature format of location. The requirement to convert between Centigrade and Fahrenheit and vice versa is burdensome so defaulting to the format of the locale removes one layer of complexity.

    We can also include:

    • Automatic correction of required formats for any input fields
    • Appropriate default values for date fields within the context of the application
    • Appropriate default time zone format based on location
    • Appropriate default currency format based on location
    • Appropriate default temperature format based on location

Working group notes

removed the first sentence: Identify common input errors.

It was decided that the original COGA Success Criteria below should be broken into three separate Success Criteria - Minimize User Errors (outlined above), Labels or Instructions, and Identify Charges.

Prevent the user from making errors

Was: Support is provided that help users complete and check their task, that includes

(may be provided via a standard personalization mechanism) (COGA Techniques 2.9 )

In forms

  1. Use known techniques to prevent errors that are relevant to the content. All standard ways of representing information are accepted as input formats, such as different ways of writing a phone number and date formats.
  2. Documented common input errors can be corrected automatically. (example spelling mistakes)
  3. Enable and identify the default format and standards of locale and allow for change of format on labels and user input (removed use the default format and standards of locale and allow for change of format)
  4. Clear visual indicators are provided that identify what information is essential, and non-essential information is clearly differentiated from essential information.
  5. Instructions are provided if there is not a label that fully describe the control or if it is not clear were to get the required information. Instructions should explain the purpose and usage of the control. (Graphics with a text alternative may be sufficient) ( A clear instruction or information is on where 99% of your target audience understand immediately what to do)

For legal and financial transactions

  1. Options that may disadvantage the user are only selected at the users specific request.
  2. All types of charges must be clear at the start of a transaction task.
  3. When a minimum is known for a type of charge it must be be made clear at the start of the transaction task. (from support the user)

For all content

  1. Non native content and sponsored content are clearly marked and visually differentiated by standardized techniques
  2. Clearly differentiate between facts and less substantiated opinions. Was rewritten from "Clearly differentiate between opinions and facts "