Full article and sampling methodd here
The money shot:
From the data you can see that with CAPTCHA on, there was an 88% reduction in SPAM but there were 159 failed conversions. Those failed conversions could be SPAM, but they could also be people who couldn?t figure out the CAPTCHA and finally just gave up. With CAPTCHA?s on, SPAM and failed conversions accounted for 7.3% of all the conversions for the 3 month period. With CAPTCHA?s off, SPAM conversions accounted for 4.1% of all the conversions for the 3 month period. That possibly means when CAPTCHA?s are on, the company could lose out on 3.2% of all their conversions!
Given the fact that many clients count on conversions to make money, not receiving 3.2% of those conversions could put a dent in sales. Personally, I would rather sort through a few SPAM conversions instead of losing out on possible income.
Your thoughts? I kinda agree with him ... 3.2% doesn't seem like too high a price to pay as opposed to the nasty income reduction WITH captcha...