While you may assume that Google local results in a simple 1 to 10 format, the 7 result SERPs as well as blended local results make it a complicated affair. If you look at any SERP that has been de-personalized then you may assume that there are 6 organic results or a total of 13 total results on the first page.
However, most of Google’s first-page SERPs usually have 7 or even 10 organic results. In addition, these could also be mixed results in which there are organic results as well as local results.
There is one trick to find out the 4 mixed results. You need to modify the “start=” parameter of Google. The start=10 URL parameter of Google actually moves to page 2 even when the first page only delivers 7 SERPs. Google too begins coding from 0 or zero, which means that SERP 10 is in reality 11 since the first page results are from 0 to 9.
You need to modify the “start=” URL parameter to any figure that is not a multiple of 10. You will now get organic results that begin with the specified position. For instance, changing to “start=7” will provide results that do not feature any local results which begin from the 8th organic ranking.
You can also indulge in reverse counting to get the actual organic results. You can specify “start=1” that will display from the 2nd rank onwards. Once you do this and compare all URLs with the original SERP, you will be able to learn about results that were not mixed as well as the actual order of appearance in case they were not influenced by the local 7 pack.
Using this trick will help you understand just how Google ranks and displays local and mixed results. You may also find opportunities for a site that may possess weak organic ranking, but may be better optimized in terms of local. In addition, you may be able to bump up sites with low organic result ranking with better SEO to improve local ranking.
The 2 algorithms used to rank organic and local seem to overlap each other and you may well witness increased verticals that include Knowledge Graph. You will certainly need an in-depth study to ensure high SERP visibility.