The ‘Study structure’ and ‘Study forms’ builder in Castor CDMS enables you to create and modify your own forms for your eCRF. Castor CDMS makes a distinction between the Study structure, Repeating Data and Surveys:

Study forms, repeating data, and surveys

Study forms: study forms are the actual “Case Report Form”. When a participant is created, all these forms will be automatically created.

Repeating data: these are the repeating forms and can be used for repeating data such as Adverse Event, medication, and repeated measurements such as blood pressure. They have a “one-to-many” (1:N) relation with the participant. In other words, when it is not known in advance how many times a specific measurement will be performed or how often an event (e.g. adverse event) will occur, use repeating data. 

For example, for 1 patient you could have 2 measurements, for another you have 6 measurements. Examples of measurements that are stored in repeating data are blood pressure, medication, adverse events.

Surveys: surveys are questionnaires that you send to participants using their email addresses or Castor Connect app. Surveys are sent in a survey package.

Visits, forms, and fields

The basic structure of your CRF is determined by Visits and Forms, which contain Fields, the actual questions.

Visits are periods in a study, e.g. "Baseline", "Visit 1" etc. These can have a specific duration, e.g. 2 months. Only study forms can consist of visits, not repeating data or surveys.

Forms are sections inside a Study Visit. A Study Visit can have as many forms as you like. Forms break up Visits, and make the CRF user friendly and less bulky. Forms are also present in your repeating data or surveys. 

Fields are the most important part, they are the actual questions in your eCRF. Each Form can have any number of questions, but we advise users to keep the number of Fields per Form low, to make sure the forms don't get too long, thus reducing user friendliness.

Questions to ask yourself when you are setting up the study structure:

1. Are the questions answered by a healthcare professional directly in Castor CDMS?
   • Use study forms
2. Do the questions have a "one-to-many" relationship?
   • Use repeating data instead of study forms if it is not known in advance how many measures will be taken/events will occur
3. Are the questions going to be asked via e-mail?
   • Use surveys and survey packages and/or Castor Connect App