Both my colleague and I worked on an article together for a client. However, he did his portion incorrectly, which I realized long after the fact because I didn't think I would have to double check his work. The article got published on our client's website already.

My colleague did the keyword research, and I "optimized" the article to get it to rank in the search engines and "be found" for the keywords he chose.

Well, it turns out he chose the wrong keywords to target, and even though I optimized the article to rank well for those target keywords, it will never rank and therefore, will never gain any traffic or sales, most importantly.

Now, this colleague is above me. He was just promoted to a more senior role, though he is NOT my boss. He is also in charge of content (blog/article) creation for this client of ours. It's really HIS baby, but I helped with it.

So my question:

How do I (a) cover myself (CYA) and let it be known that it wasn't my own screw up? (b) do this diplomatically without stepping on his toes???

Thanks!!!