For example, try searching the following string in quotes: "the SERP should stay the same".
https://www.google.com/search?q=%22the%20SERP%20should%20sta...
Now, the logical presumption, assuming Google works as people say it does, is that each result will contain that exact string. If no results contain the string, then you should receive no results.
However, for me, results are returned. Did each of the results from that search contain this exact string? For me, they did not.