Pay 40% less for ads with this (research)

A study of 9,000 direct response campaigns on Twitter found that:

1. Tweets with urgency words like hurry, fast, quick, running out, and limited time have a 10% lower cost per acquisition (CPA) and a 10% CTR.
2. Tweets that fall in the range of 40-60 characters have the lowest CPA.
3. Tweets that ask a question have a 16% higher CTR.
4. Tweets that promote a contest have a 40% lower CPA.

Looks like worth testing for other ads channels too.

Source: blog.twitter.com/2016/how-to-make-your-dr-tweet-copy-more-effective