Claude Opus 5.5 uses 95% fewer em dashes, but its answers are getting longer

Arena's analysis found Claude Opus 5.5 writes more simply than Opus 5: em dash usage dropped from 15.2 to 0.8 per 1,000 words (a 95% reduction), and semicolons fell from 6.10 to 1.64. Average sentence length shrank from 12.14 to 10.03 words, but average answers grew from 453 to 481 words.

• Em dash usage fell from 15.2 to 0.8 per 1,000 words, a 95% drop
• Semicolon usage dropped from 6.10 to 1.64 per 1,000 words
• Average sentence length shrank from 12.14 to 10.03 words
• Average answers grew from 453 to 481 words, the longest among Opus models