Personalized first lines lift reply rate from 2.4% to 7.1% — automation costs 4.7 points

Personalized first lines lift reply rate from 2.4% to 7.1% — automation costs 4.7 points

A/B across 2,000 sends, identical targets, split by intro line (n=2,000).

— Template merge-tag intro ('Hi {FirstName}, love {Domain}'): 2.4%
— Hand-written one-line reference to a specific article: 7.1%

Chart in words: reply rate nearly triples the moment the opener proves a human read the page.

The tradeoff is throughput — hand-writing caps an operator near 40 emails/hour versus 400 fully automated. But automation's volume cannot close the conversion gap; you would need 3x the sends to match.

Automate everything except the first line — that one sentence carries most of the reply lift.