How do changes in Source Data Verification settings impact a study?

The Source Data Verification (SDV) settings can be updated at any time. This includes the study level settings to either include or exclude screen failed subjects, or to require different levels of SDV (full, targeted or none). For targeted SDV, you may also update the SDV strategy associated with a site or the SDV settings for a specific question in form design.

For more information about SDV settings and use cases see Understand source data verification.

Whenever the SDV configuration is updated, your study is impacted in different ways and you must consider the following:

Any changes to a study's Source Data Verification settings are only reflected on a subject once a visit for that subject is started subsequently. For example, if new questions are made SDV required making the whole visit verification required for the subject.
If you update the Include Screen Failures setting from Yes to No after adding subjects in a specific study mode (Testing or Production), any screen failed subjects previously selected for the Initial Subjects or Remaining Subjects pools will be excluded. Any data that was previously verified remains verified, but any subsequent data changes will not impact the SDV status of the subject.

Note:
Even when screen failed subjects are excluded, questions marked as SDV for All Subjects remain SDV required for them.

In the case of a previously selected screen failed subject getting excluded, a new subject is to be selected only if the site's current strategy requires replacement. For example, if you had selected three initial subjects and one of them was a screen failure and gets deselected, a new subject will be selected to meet the initial subjects count. But, if you also changed the strategy to two initial subjects, no new subject would be selected since two initial subjects would still remain.
If you update the Include Screen Failures setting from No to Yes, no changes occur for existing screen failed subjects, although they will be eligible for SDV moving forward, based on your existing SDV strategy's algorithm.
Other changes to the selection criteria for the targeted SDV subject pool, derived from changes on an SDV strategy assigned to a site, are reflected once the next subject is selected for SDV.
- If, in the SDV strategy, you increase the number of initial subjects after remaining subjects have already been selected for the SDV pool, the system selects the immediate next subjects that were added or screened for the initial subjects pool. Then, the system makes a new calculation for the remaining subjects, and randomly selects additional subjects if the current selection drops below the specified percentage.
- If the SDV strategy changes to reduce the number of subjects requiring SDV, a subject already selected for SDV can not be deselected. The new strategy will apply to newly entered subjects and the system will adjust to match and maintain the percentage of selected subjects as the total number of subjects increases.
For more information, see How are subjects selected for targeted source data verification?
Forms, visits, or subjects with a Verified status or that do not require SDV can change status to Verification Required. This may happen in the following situations:
- Questions requiring SDV are added or updated through a change in SDV settings.
- A parent question is updated and the new answer triggers the display of a dynamic question that is SDV required, or a dynamic form with at least one question that requires verification.
- A subject is now selected for the targeted SDV subject pool (Targeted SDV only).
The number of questions requiring SDV may decrease and this can change the status of a visit from Verification Required to Verified. For example, if a study manager changes the SDV settings from 100% to Targeted SDV.
All verification records in the Answer & Visit History are attributed to the user who performed the verification actions. However, if the SDV requirements of a study change, the verification records associated to the change are attributed to AutoSDV and display the time when the SDV status was updated.