I am in process of pruning my sites for low quality/thin content. The issue is that I have multiple sites with 40k + pages and need a more efficient way of finding the low quality content than looking at each page individually. Is there an ideal way to find the pages that are worth no indexing that will speed up the process but not potentially harm any valuable pages? Current plan of action is to pull data from analytics and if the url hasn't brought any traffic in the last 12 months then it is safe to assume it is a page that is not beneficial to the site. My concern is that some of these pages might have links pointing to them and I want to make sure we don't lose that link juice. But, assuming we just no index the pages we should still have the authority pass along...and in theory, the pages that haven't brought any traffic to the site in a year probably don't have much authority to begin with. Recommendations on best way to prune content on sites with hundreds of thousands of pages efficiently?  Also, is there a benefit to no indexing the pages vs deleting them? What is the preferred method, and why?