Google is experimenting showing app indexing results to users who do not have the app already installed, if Google feels the app result is a good result for the particular search query.  And the app indexing ranking signal applies to those results too, for searches coming from an Android.

Google hosted a Webmaster Office Hours today with discussion about app indexing, and one of the question was whether app indexing would work for users who do not currently have the app installed.

Krzysztof Bielski from Google answered the question.

We are experimenting right now and we are displaying within Google search results, also results for when you don’t download the application, and you ask some particular query, we think that the results for this query would be found in one of the applications, we suggest to users downloading a particular app.

So basically to answer the question, no you don’t have to have the app installed to see the benefits of app indexing.

And as well, the information that we released in April this year that app indexing is one of the signals for ranking, it also applies to the users that didn’t install the app.

When Google wrote about app indexing back in April this year, they did note that Google was “starting to use App Indexing as a ranking signal for all users on Android, regardless of whether they have your app installed or not.”  At the time it seemed that specific app indexing results were only being triggered for those who had the app installed and not just searchers in general.

However, I suspect there are many who don’t realize or remember that the ranking signal applies to search results even when the searcher doesn’t have the app already installed, and this will be even more important now that Google is actually experimenting with app indexing results for searchers without the app.

While mobile views are ramping up, this will likely put more pressure on business to consider having their own app, but even as they said in the Hangout, the number of installed apps people actually use is fairly low.  It is pretty common for someone to install an app, use it once, then forget it is buried 5 pages deep in all the app icons on a mobile.  This is a slide from the App Indexing Hangout that illustrates this:

On the positive side, app indexing does help solve this problem, and remind users that they do have that app installed, even if they don’t remember.