Canonical or noindex for almost(80-90%) duplicate content?

Question

I have a site where I provide solutions to problems/questions. In my CMS, the 'Question' and 'Solution' are two different content types. The solutions are embedded within the Question pages.

For example:

Question: What is foobar?

The length of the question can range from 4-5 words to 100+ words.

Solution: Foobar is Lorem Ipsum.

It will be one to multiple paragraphs answer. It has its own URL too.

I want only the question pages (example.com/question/what-is-foobar) to be viewable to users.

Problem:

example.com/question/what-is-foobar

and

example.com/solution/foobar-is-lorem-ipsum

are being seen as duplicate content which is quite obvious.

Another problem is that the Solution's pages are appearing on search results which I don't want. I want only the question pages to appear on search results.

Now, to fix the issue, I have two alternatives. In my solution pages, I can either:

1. Use noindex.

   <meta name="robots" content="noindex, follow">
   

2. Use the canonical tag.

   <link rel="canonical" href="example.com/question/what-is-foobar" >
   

3. Use 301 redirects but that does not look like a good option as I will have to keep adding redirects.

Which one is more suitable in this situation? I think canonical would be the better one. However, I am not sure because of the length of the questions. If the question itself has, say 80-100 words, does it make the two pages not suitable candidates for canonical URLs? In other words, is it okay to use canonical tags even when two pages are 80-90% similar?

Answer 1

The Canonical tag would be the best implementation among the two you've proposed. Your solution page should point the canonical tag to your question page. As Google says, the canonical tag:

"Can map an infinite number of duplicate pages."

Also, this from Google:

"Don't use noindex as a means to prevent selection of a canonical page. This directive is intended to exclude the page from the index, not to manage the choice of a canonical page. "

Check out Google's detailed explanation on the matter: https://developers.google.com/search/docs/advanced/crawling/consolidate-duplicate-urls

If you are considering other solutions, here are a few alternative scenarios for you:

• Scenario 1: you can use a single page where you have your question and answer, but hide the answer from appearing in the search results. To do this, you can use the data-nosnippet HTML attribute:

https://developers.google.com/search/docs/advanced/robots/robots_meta_tag#data-nosnippet-attr

Using this technique, you can hide the answer from the viewing user using Javascript, Jquery, or similar, until, for example, they click a button to see the answer.

• Scenario 2: you can structure your page to become like paywalled content. This method will prevent Google from considering that you are cloaking content, which is against their guidelines.

https://developers.google.com/search/docs/advanced/structured-data/paywalled-content

Using this technique, Google will understand that the marked content is not to be shown on the SERPS, because it requires membership or the user registering or clicking somewhere.