I'd like to see a recommendation of when to delete keywords that haven't been performing
Thanks for your feedback. We are working on this feature, stay tuned!
Calvin Wang commented
Currently we can see exactly how well each keyword is performing in terms of clicks and impressions. If a keyword is getting no impressions, then it doesn't hurt to keep it around (perhaps the rare impression will be super relevant and yield a high CTR). If a keyword is getting a lot of impressions but very few clicks, then that's a signal that the keyword itself is not relevant enough. The $1M question is how do you know when the results are statistically significant. It would be nice if Bing Ads could perform statistical analyses and make recommendations based on significant results.