Dealing with links that point to a non-canonical URL?

[MelissaLB]

As some of you know we have posted our site in the Site Review section to get some input on how to solve our recent massive decline in the Google serps. Our developer is putting together a plan based on findings and suggestions from myself and a few regular posters here in the forums. There is one point regarding canonical urls and links pointing to non-canonical urls out in the web. We could use some advice on this and here is his question:

We'll be looking to move to a model whereby a product is always linked only by its "generic URL" (eg. website.com/store/product_name) and not the license/category specific URLs that show click path.

With regards to dealing with URLs that already exist out in the wild with licenses and categories in the URL, what's the best way to deal with those? We *could* 301 redirect those to the generic page like we're doing with invalid links, but I'm concerned that any search-engine position those links already have might be lost as a result. My research shows that a canonical tag on the license/category version of the product pages that point to the generic page might be a better way to "transfer" any existing position data over to the appropriate page, but at the same time, I'm worried about keeping those pages active due to duplicate content issues, etc.

Is there a correct way to deal with these occurrences of links pointing to non-canonical urls?

Please let us know and feel free to weigh in over in the Site Review located here: [webmasterworld.com...]

Thanks in advance

[TheMadScientist]

My research shows that a canonical tag on the license/category version of the product pages that point to the generic page might be a better way to "transfer" any existing position data over to the appropriate page...

I find that fascinating... Are you saying rel="canonical" works better than a 301 redirect? If so, how are you testing?

Rel="canonical" is a 'suggestion' while a 301 Redirect is a definitive solution, which makes me wonder a bit... It's interesting if that's actually the case since Google says 301s are the preferred method of defining a canonical page.

Personally, in answer to your question, I would definitely 301, mainly because IMO it's the right way to do it.

[jimbeetle]

Agree with TheMadScientist. The rel canonical is not under your control. SEs can interpret it any way they like. It definitely is not future proof, unlike the 301 which cannot be misinterpreted and is controlled sole;y by you.

[MelissaLB]

Thanks guys. @themadscientist I'm not sure exactly how they are testing, that was a question from one of our developers. It's actually a bit too technical for me to comment on. ut with these responses and one from aakk9999 in our Site Review thread, we seem to have our answer.
many thanks. a great help indeed!