What does the function words in keyphrase check do?
The assessment checks whether the keyphrase consists of function words only and warns you if this is the case. It might be that you were distracted while typing in your keyphrase and instead of entering “the best SEO plugin” you only entered “the”. We warn you that your keyphrase choice is suboptimal.
Why are function words in keyphrase important for SEO?
Search engines, like Google, ignore function words most of the time. This is because these words tend to have a very generic meaning, that does not help with figuring out the actual topic of the copy. That’s why we at Yoast think that trying to rank for a function word (or a bunch of function words) is not a good idea and we give you this warning.
How to improve?
As I said, it can just be that you forgot to finish entering your focus keyphrase. In this case, simply go ahead and finish your keyphrase as you normally would. We will reanalyze your copy and the warning will go away. Note, however, that any function word that you enter in your text gets neglected by the Yoast plugin (except for one assessment), so you can just as well choose to not enter them at all.
It can also be that you actually mean to rank for a phrase that consists of function words only. For instance, if you are writing about a meme “Why would you do that?”. This is quite a rare case, of course, but it can happen. People who will search for such content online will likely use exact-match functionality by Google: Instead of simply typing their search request in, they will use double-quotes around it, to make sure all words are found and in this precise order. Good news! You can you exactly the same when working on your article with the Yoast plugin. Just add a double quote before and after your keyphrase and voilà, only exact matches of your keyphrase are now found in your copy and the warning is gone.
If you do not recognize yourself in the first two scenarios, it is quite likely that you need to put a little more work in your keyword research. We know that it can be quite daunting, especially in the beginning, but quality keyword research will always pay off! And if you really want to nail your keyword strategy, join our A to Z keyword research strategy course!