The REDCap user interface provides an intuitive method to securely and accurately input data relating to research studies. Figure 2 shows a typical CRF view. Each form is accessible only to users who have sufficient access privileges set by the research team. Forms contain field-specific validation code sufficient to ensure strong data integrity. In addition to checking for mandatory field type (e.g. numeric entry for systolic blood pressure), embedded functions also check data ranges (e.g. 70–180 mmHg) and alert the end-user whenever entered data violates specified limits. Data fields may be populated using text fields or through embedded pull-down boxes or radio buttons where the end-user is shown one value and a separate code is stored in the database for later statistical analysis (e.g. 0=No, 1=Yes).
