In a recent video published on Google’s Webmaster Help Channel Matt Cutts, Head of the Web Spam Team at Google answered the question: “Do Google use the same algorithm to rank all the results on page 1, or different algorithms for a wider variety in the results? (Pos. 1-3 – primary focus on freshness Pos. 4-6 – primary focus on back links Pos. 7-10 – primary focus on social signals)”
This is an interesting question and I have heard similar questions before, Matt goes on to answer by stating “In general the rankings are not different for positions 1 to 3, and 4 to 6 and 7 through 10. It’s the same algorithm that returns lots of different web results, you know a hundred or even a thousand and then with those we just sort them in the order of what we think the trade-off of relevancy versus reputation, so we want something is very relevant, but also as reputable we can find.”
Of course Matt is only referring to standard search results here so you might expect that different algorithms apply to new or local results.
So if you have ever considered using different SEO tactics to achieve rankings within certain blocks of the search results, don’t. Just concentrate on creating a good quality site which is the best in your niche.
Here is the video with the answer from Matt Cutts in full: