It's book reader elitism. There is always an author and fandom that people feel the need to incessantly criticize or put down so that they feel better about themselves. I've personally seen that many of the criticisms are from people that don't even typically read her genre, so their criticisms of her work are literally what other people love. Colleen writes specific types of books for specific audiences, and she clearly excels within that niche. People will read Verity because they saw it marked as a thriller but there is no way one should expect an actual thriller from Colleen. I don't know. I feel people should do their research before randomly buying books because they saw it on best seller list.

Yes, she sometimes punches above her weight by trying to incorporate genres/topics that aren't her forte, but out of everything she has published I don't see how books like Verity and that one about domestic abuse mean she is a terrible author overall or her readers aren't smart or sophisticated.

Failure rates are determined during clinical trials in smaller populations where they also survey compliance to use of the contraceptives and factors that affect compliance. So these rates are obviously not completely accurate in all populations/contexts.

The failure rate is the difference between the expected number of pregnancies (per 100 people) with no contraceptives and the expected number of pregancies (per 100 people) correctly using that contraceptive. The efficacy rate is 100 minus the failure rate.

So a failure rate of 2% means an efficacy rate of 98%.