Build automated queries with data validation explains the mechanism. This page gives you the rules most protocols need, ready to copy.

🔑 Prerequisite: eCRF Builder (Edit), and a study in Draft or Suspended status.

Pick the severity first

Severity	Use it for
Information	A reminder that needs no action: "Value above 140, record an AE if clinically significant"
Warning	A value that is possible and unusual. The site confirms or corrects, and Datacapt raises an automatic query
Exclusion	An answer that makes the subject ineligible under the protocol
Disqualified	Screening forms sent to participants, where a wrong answer ends the questionnaire

Datacapt checks a rule when the site saves the answer, not while typing.

Ranges

Check	Question	Rule
Systolic pressure plausible	`SBP`, Number	Lower than 70 → Warning. Second rule: Greater than 220 → Warning
Temperature in °C, not °F	`TEMP`, Number	Greater than 45 → Warning "Check the unit: enter °C"
BMI eligibility 18.5 to 30	`BMI`, Calcul	Lower than 18.5 → Exclusion. Greater than 30 → Exclusion
Pain score triggers AE reminder	`PAIN`, Rating	Greater or equal 7 → Information

💡 Tip: set Min number and Max number on the question for values that cannot exist (a weight of 900 kg). Keep data validations for values that can exist and need a second look. The first blocks entry; the second opens a conversation with the site.

Dates

Check	Question	Rule
No date in the future	Any Date/time	Tick Disable future dates on the question. No rule needed
Consent before any procedure	`VISIT1_DT`	Before, compare to Date linked `CONSENT_DT` → Warning "Visit date precedes consent"
AE end after AE start	`AEENDT`	Before, Date linked `AESTDT` → Warning
Adult at inclusion	`AGE`, Calcul (Calculate age)	Lower than 18 → Exclusion
Sample within 2 hours of dose	`PK_DTM`	More than (after), period 2 Hours, Date linked `DOSE_DTM` → Warning

Visit windows

Datacapt has no window setting on the visit itself. Two blocks do the job.

Step	Block
Show the target date to the site	A Calcul question, type Calculate Date / Time: reference `V1_DT`, 14 Days
Flag a visit outside Day 14 ± 3	On `V2_DT`: Less than (after) 11 Days, Date linked `V1_DT` → Warning "Visit 2 before window". Second rule: More than (after) 17 Days, Date linked `V1_DT` → Warning "Visit 2 after window"

Cross-visit and cross-form checks

A rule can read a question from another form or another visit as an extra condition.

Check	Rule
Pregnancy test required for women	On `PREG_RES`: condition `SEX` Equal to Female (from the demographics visit)
Weight change above 10 %	A Calcul `WT_CHG` = `({V3_WEIGHT}-{V1_WEIGHT})/{V1_WEIGHT}100`, then Greater* than 10 → Warning, and Lower than -10 → Warning
Dose matches weight band	On `DOSE`: Greater than 500 with condition `WEIGHT` Lower than 50 → Warning

What a validation cannot check

The content of a Text input, a Checkbox or a File upload question. For a required format such as initials, use a Dropdown or a Number question where you can.
A rule limited to one visit when the same variable name exists in several. Each visit has its own variable (V1_SBP, V2_SBP), so write the rule on the one you target.
A question with Hide in eCRF switched on. The Builder says "Data validation is unavailable when Hide in eCRF is enabled".
Two visits compared without a date question in each. Visits carry no date of their own, so add a visit date question at the top of each visit.

Test each rule twice

Enter one value that must fire the rule and one that must not, on a draft subject, logged in with a site role. Record both in your validation file with a screenshot. An inspector will ask how you tested your edit checks, and Datacapt deletes test subjects at go-live.