In what scenario would you be unable to use Head Start?

Head Start is a feature in Marketo that allows for the scheduling of campaigns based on the performance of past A/B tests. It leverages data from these tests to optimize the timing and audience for future outreach. Thus, the inability to use Head Start is directly linked to the absence of A/B testing. When A/B tests are not utilized, there is no prior performance data to inform the Head Start feature, making it ineffective.

In contrast, the other scenarios listed do not inherently preclude the use of Head Start. Program approval processes can occur independently of testing strategies, and static lists of attendees might still be leveraged within a framework where A/B testing is used elsewhere in the program. Launching a new program type also does not directly affect the usage of Head Start if the relevant A/B testing data exists from previous campaigns. Therefore, the situation where A/B testing is not in use is the only scenario where Head Start cannot be applied effectively.