Before using the information found, you should assess its quality and relevance. The following methods can be applied to make sure every source you plan on using in your research assignment is reliable:
Be aware that Google use algorithms (PageRank) to filter, or tailor, the search results, based on previous searches you have done – the sites you have viewed, what you clicked on and other data that can be gathered from your browser. So the exact same search, using exactly the same search words, can return different results for different individuals.
Pariser, Eli. "Beware online filter bubbles." Filmed February 2011 in Stockholm, Sweden. TED video, 8:47.