Required Questions and Validation Rules

Required questions and validation rules improve data quality when an answer is necessary for analysis, eligibility, Flow, quotas, or completion. They also add friction, so reserve them for fields that genuinely need a usable value and make the correction path obvious in Preview.

In Domandata, the Required slider is in the question card header: optional, requested, or required. Survey Options has the same slider for every answerable question at once. Text-response validation lives in the question options area after you choose Text Response as the question type.

1. Step 1: Open Block Builder. Select the survey and go to the block that contains the question.

   Step 1: Open Block Builder

2. Step 2: Set requiredness in the card header. Slide the control beside the question type label to optional, requested, or required. Requested asks once before advancing; required blocks a blank answer. Informational content blocks do not collect answers, so they do not need this control. To apply the same setting to every answerable question, use the matching slider in Survey Options.

   Step 2: Toggle Required

3. Step 3: Open the question options. For typed fields, choose Text Response and find the Validation select in the options area.

   Step 3: Open Question Options

4. Step 4: Choose the validation kind. Select Integer, Number, Email, Phone Number, Zip Code, Date, Contains, or Python only when the rule matches the research protocol. Date validation adds its own output format (YYYY-MM-DD, MM/DD/YYYY, or DD/MM/YYYY), uses that format as the default example, accepts recognizable typed date formats and corrects them on blur, and rejects calendar-invalid dates like February 30th. Turn on Show calendar picker when respondents should also be able to choose from a themed calendar.

   Step 4: Choose Validation Kind

5. Step 5: Add bounds or rule details. For numeric rules, fill in Min and Max when values outside the range should be rejected.

   Step 5: Add Bounds

6. Step 6: Test the error state. Open Preview, leave the answer blank or intentionally enter an invalid value, and confirm the respondent can tell what to fix.

   Step 6: Test Error State

1. Step 1: Identify critical fields. Mark only protocol-critical questions as required, such as consent choices, screeners, assignment variables, or primary outcomes.

   Step 1: Identify Critical Fields

2. Step 2: Choose the right question type. Use Choose Research Survey Question Types when the response format is still uncertain.

   Step 2: Choose Question Type

3. Step 3: Add validation for typed answers. Use Text Response validation for numeric, length, contains, or custom checks.

   Step 3: Add Validation

4. Step 4: Name validated variables. Give important validated fields clear question names before they feed Flow, quotas, or exports.

   Step 4: Name Variables

5. Step 5: Preview invalid answers. Use Preview to test blank answers, invalid numbers, and edge cases.

   Step 5: Preview Invalid Answers

6. Step 6: Inspect exports. Submit a test response and confirm the cleaned values appear correctly in Export.

   Step 6: Inspect Exports

Deploy's Instrument Review panel checks for this automatically: a Text Response question whose title clearly asks for an age, birth year, date of birth, ZIP/postal code, phone number, or email address, but has no matching validation rule turned on, shows up as a finding with a one-click fix that turns on the right rule (and, for age or birth year, a plausible min/max) directly from that question's config.

• Eligibility age: use Text Response with Integer validation and a minimum bound that matches the study protocol.
• Allocation variable: use Multiple Choice or Dropdown with fixed options, then name the variable before using it in Flow.
• Completion code confirmation: keep the field optional unless the code is required before the respondent can receive credit.
• Open-ended explanation: avoid strict validation unless the analysis plan needs a minimum length or specific phrase.
• Sensitive demographics: consider optional answers or a Prefer not to answer option so missingness reflects a real respondent choice.
• Date of birth or event date: use Text Response with Date validation instead of a free-text field, so a respondent can't submit "13/45/2026".

For most question types, a required question blocks advancing until the respondent gives any answer. A few types have their own rule:

• Dropdown: the respondent must pick an option; leaving the placeholder selected doesn't count.
• Slider: the respondent must move the slider. A required slider left untouched shows "Move the slider to choose a value."
• Drag to Order (full ranking): the respondent must either reorder the items or choose Keep This Order to confirm the starting order is their answer.
• Audio questions with a typed alternative: a typed answer satisfies the requirement in place of a recording.

By default, respondents don't see a mark next to required questions. They find out a question is required when they try to move on without answering it. To show an asterisk (*) after the title of every required question, open Deploy, expand the Structure card, and turn on Mark required questions with an asterisk. Requested and optional questions never get the mark.

Screen readers announce "required" on required questions whether or not the asterisk is turned on. To have every new survey start with the asterisk on, turn on the same setting under Settings → Advanced → New Default Survey.

Some checks need to compare two or more questions to each other rather than validate one field alone — a confirm-email pair that must match, or a budget allocation that must sum to a fixed total. A block's Cross-field rules menu item (in the block's actions menu, or right-click the block) defines a Must match or Must sum to rule across any of that block's Text Response, Multiple Choice, Dropdown, or Slider questions. Unlike per-question validation, a cross-field rule blocks the respondent from advancing past the page in real time with a custom message you write.

This is different from the Impossible Combination quality rule: that rule flags an already-submitted response for review, it does not stop the respondent from submitting it in the first place. Use a cross-field rule when the answer combination should never be submittable at all; use Impossible Combination when you want to review borderline cases after the fact rather than hard-block them.

Do not require sensitive demographic questions unless the research protocol needs them. For sensitive or identifying fields, consider inclusive response options such as Prefer not to answer and review Privacy and Anonymity in Research Surveys.

• Survey Data Quality Checks
• Attention and Manipulation Checks
• Custom Code in Survey Questions