Criteria for Inclusion
In order to generate year-over-year comparisons, customers had to be a Turnitin customer before January 1, 2011 and remain a customer through January 1, 2013.
Time-Aligning Accounts Based on Usage
In order to provide comparable measurements between different accounts, this study aligned customers based on their years of use rather than the year in which the customer began using the product. For example, a school (call them Customer A) who began using Turnitin in 2010 would have three years of usage (2010, 2011, 2012) and a school (Customer B) who began using Turnitin in 2008 would have five years of usage. These customers were aligned based on their years of usage (First Year, Second Year, Third Year, etc.) in order to avoid inaccurate comparisons of the results customers realized in a calendar year (for example comparing results in 2011) when Customer A would be in their second year of usage and Customer B would be in their fourth year of usage.
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Calculating the First True Usage Start Year
Schools who subscribe to Turnitin in a given year do not necessarily generate meaningful usage information in the first year under license. In particular, Turnitin deployments at larger institutions are often part of larger efforts, including changes academic integrity policies, adoption of a new learning management system and professional development and training initiatives.
For example, a school of 4,000 students might only submit 40 papers to Turnitin in the first year but then increase submission volume to 3,000 in the next year. Using the 40-submission year as a baseline measurement would skew the analysis because it is not a sufficient sample size. In order to control for this occurrence, this study calculates what we call the “true usage start year” by totaling the lifetime submissions of the account and determining the first true usage start year in which the customer submitted 10 percent of that total.
Once accounts are aligned based on years of true usage, we generate a sum of originality submissions for all accounts as well as a sum of all papers with levels of unoriginal content above 50 percent for the first year of usage. By dividing the sum of 50-100% unoriginal into the total submissions, we arrive a percentage of unoriginal papers. By calculating this figure for each year of usage and comparing it to the first year of usage, we can measure calculate the change in highly unoriginal papers over time.