Reply rate jumped from 4.1% to 11.3%

Reply rate jumped from 4.1% to 11.3%

One agency, two quarters, n=2,840 cold outreach emails to the same prospect type (SaaS blogs, DR 40-70). The only deliberate change between cohorts was subject-line length.

Reply rate by subject word count:
— 10+ words: 3.9%
— 7-9 words: 6.2%
— 4-6 words: 11.3%
— 1-3 words: 7.0% (read as spam, dipped back down)

The curve peaks at 4-6 words then falls off as brevity tips into vagueness. Link placement rate tracked replies almost linearly: 1.1% to 3.4%.

Sample skews B2B; consumer lists may differ. Directional but the gap is too wide to be noise.

Cap outreach subject lines at six words and test against your 10-word control.