After launching her email campaign, Eliza is interested to see how it’s performing – and while the good news is that her click-through rates are sky high, her clicks per unique open are much lower than expected. Group the following email elements based on what she’s doing well and what she may need to check.

The provided grouping is correct because Eliza’s high overall click-through rate, contrasted with her low clicks per unique open (also known as Click-to-Open Rate or CTOR), reveals a specific disconnect between her email's packaging and its actual content. The elements under Doing well (Subject line and Preview text) are the external factors that control whether a subscriber decides to open the email in the first place; because her unique open volume is high enough to inflate that denominator, it proves her hooks are incredibly compelling. On the other hand, the elements under Need to check (Message structure, Images, Call to action, and Copy) are internal factors; a low click-to-open ratio means that once curiosity brings readers inside, the visual layout, confusing imagery, unpersuasive writing, or poorly placed buttons fail to deliver on the subject line's promise, causing subscribers to leave without clicking through.