Disallow in Robots.txt VS NoIndex tag

I have a page on my site that I do not want indexed and want to know the most effective way to go about this. Should I put the NoIndex tag in the HTML of the page, or should I disallow the page in my Robots.txt file. I remember hearing that one strategy is more effective than the other. What are your thoughts?

robots.txt will work just fine. Actually, I don't see a reason to not using it.

In theory, you can even save a bit of bandwidth, because a bot will need to load a page before it gets access to meta, while robots.txt is processed without docs being opened at all. Not a big deal, though.

And still both methods do not guarantee that a file won't be actually crawled. They merely tell bots to not do this, so some not so civilized bots still may ignore these instructions. If you really want to block a file from being opened, use rewriterule in your apache conf.

The "noindex" attribute and the "disallow" directive do different things.

1. "noindex" attribute: Google robots will crawl the page and see that you do not want it to be indexed. Google will not show the page in the SERP's.

2. "disallow" directive: Google robots will not crawl the page. The URL of the page will be indexed by Google, but not its content (as Google did not crawl the page). In some particular circumstances, the URL of the page could appear in the SERP's.

So the "noindex" attribute is the safest solution. If the page should not be seen by unauthorized persons, you better use a user/password authentication system to give access to the page rather to rely on search engines.

Jean-Luc