Once you've added a form and section you can add a field using the Add a field link in the section. There are several field types to choose from depending on the type of data you are collecting.

In this article

Field label

The field label is shown on the form in Red Pill above the control for entering data. It is the question or information sought. When adding/editing a field, the label can be formatted (e.g. bold, italics, underline, strikethrough, subscript/superscript, and coloured text), and a hyperlink can also be added. This formatting will be shown in Red Pill.

Formatting a field label

Field name

The field name is used to name the underlying database column. Because of this, field names must be alphanumeric, start with a letter, and have a maximum length of 32 characters. The name is used when downloading data from Red Pill.

Defining the field name

Field actions

You can edit a field, add a new rule to the field, duplicate and delete a field by clicking on the corresponding icon. Click on the field label to show or hide details about a field and the actions that can be performed. Change the position of a field within the form by dragging it to the right place. Fields can be moved within and between sections.

Field actions

Field rules

You can add rules to most fields. Rules specify the conditions that the field value must satisfy when the form is completed in the Red Pill application. If rules can be added to a field, there will be an Add a rule link available.

The rules that are available depend on the type of field and its position within the form. Several rules can be combined for a single field.

  • Automatically convert to uppercase - available for text fields
  • Required if - make the field required if a previous field has a specified value
  • Required unless - make the field required unless a previous field has a specified value
  • Skip if - skip entry of the field if a previous field has a specified value
  • Skip unless - skip entry of the field unless a previous field has a specified value
  • Pattern match - the field value must match the specified regular expression
  • After - the date entered must be after that of the specified field
  • Before - the date entered must be before that of the specified field
  • On or after - the date entered must be on or after that of the specified field
  • On or before - the date entered must be on or before that of the specified field
  • Show message if - show a message if the field has the specified value

Please see Field rules for more information.

Field type

There are different types of fields available to suit your requirements.

Form with every field type in Red Pill

Single line text

Use for descriptive data such as initials, medication name or adverse event. A maximum of 80 characters are allowed.

Adding a text field

Paragraph text

Use for recording longer descriptions or notes. There is no limit to the amount of text that may be stored.

Adding a paragraph text field


Use for recording numbers. Decimal places and whether the number can be negative are controlled by the Format option. For instance ### format allows positive integer numbers from 0 to 999 only. -#.## allows numbers from -9.99 to 9.99. Units can be added.

Both hard and soft ranges can also be specified for number fields to limit values or warn of unusually low or high values. When a value outside the hard range is entered in Red Pill, a validation error message will be displayed, which requires either a change to the value entered or providing a justification for overriding the validation check before proceeding. When a value outside the soft range is entered, a popup warning message appears alerting the user that the value may be incorrect; the user must dismiss the alert before proceeding.

Adding a number field


Use for recording dates in dd/mm/yyyy format. Options are available to limit dates to past dates (which includes today) or future dates.

A date field can also be defined as the Date of withdrawal, which refers to the date when the participant withdraws or is lost to follow-up. When this date is entered in Red Pill, the subject is marked as withdrawn, and any visits due after this date will become inaccessible. Forms that were completed before this date will remain accessible and may be viewed and edited in the normal way. If multiple withdrawal date fields are specified, the earliest value will be used.

Adding a date field


Use for recording boolean data. Yes/No fields are presented as a drop-down select control in Red Pill.

Adding a yes/no field


Use for recording categorical variables such as sex or ethnic group. Categories are specified with a semi-colon-separated list of values or by pressing Enter after you type each category. Categories are presented as a drop-down select control in Red Pill unless the field is required and has 3 or fewer values. In this case the categories will be presented as radio buttons.

Adding a category field

Clock time

Use for recording the time of an event in 24-hour clock format (e.g. 19:50).

Adding a clock field

Elapsed time

Use for recording durations in hours and minutes (e.g. 36:30).

Adding an elapsed time field


Use for fields that need to be selected by ticking a checkbox. This category is useful, for instance, for 'tick all that apply' answers.

Adding a checkbox field


Use to add arbitrary text to a form. It does not store data. Formatting options include lists, text alignment and font size, in addition to bold, italics, underline, strikethrough, subscript/superscript, coloured text and hyperlinking.

Inclusion/Exclusion criterion

Use for recording participant eligibility questions. When the field type is inclusion criterion, the answer must be Yes when entering data on Red Pill; on the other hand, for exclusion criterion, the answer must be No. The user will otherwise see a validation error message. When questions using these field types are located on the randomisation form, randomisation will not take place if they are answered incorrectly. 

Validation error message in Red Pill when inclusion criterion is answered as No

Required fields

All field types except explanation can optionally be set as required. The user will see an error message for this field if they skip it when entering data in Red Pill. A required field will be indicated with a red asterisk on both the CRF builder and Red Pill.

Personally identifiable information (PII)

Fields can optionally be set as PII. The value will be encrypted when stored in the Red Pill database. Viewing encrypted PII fields is restricted to roles with the PII permission.


Help can be added to any field to provide instructions or additional context to the user. The help is shown as green text under the field label in Red Pill. 

A field with help in Red Pill

Other options

Other options such as field size, number format, hard and soft ranges are shown depending on the field type chosen.

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