Final answer:
Two types of evaluations, monitoring and postmortems, are indeed essential in a campaign; monitoring is ongoing while postmortems happen after the campaign ends, and both are key for meeting objectives and improving future campaigns.
Step-by-step explanation:
The statement regarding the necessity for two types of evaluations in a campaign, specifically monitoring and postmortems, is true. Monitoring allows for the tracking of a campaign's ongoing progress and effectiveness in real-time. It lets campaign managers make adjustments as needed to reach campaign objectives. On the other hand, postmortems are conducted after a campaign has concluded. They assess what worked, what didn't, and the overall performance of the campaign. This evaluation is crucial for learning and improving future campaigns. Therefore, both monitoring and postmortems are essential components of an effective campaign strategy.