After a piece of work has been submitted to Turnitin, the system analyses the text for matching sources. The resulting originality report 'scores' and annotates your work and produces the percentage of the content which matches sources in its system (colour coded for ease of identification). Don't worry if this number looks high; it is perfectly normal for an assignment to match against some of the database. If you have used quotes and referenced them correctly, there will be instances where a match will be found. The similarity score simply makes you or your lecturer aware; this can then then be used to determine if the match is or is not acceptable.