This case-sensitive code system http://hl7.org/fhir/uv/sdc/CodeSystem/entryMode defines the following codes:

Code	Display	Definition
sequential	Sequential	Questions are displayed one at a time. Previous questions and submitted answers cannot be viewed or edited.
prior-edit	Prior Edit	Questions are only displayed once prior questions have been answered (or if optional, skipped). Previously answered questions are available for viewing and potentially editing
random	Random	All enabled questions are visible and accessible to the user. They may complete questions in any order.