are trying to cheat. Methods of secretly signalling the right answer to friends are quite varied, ranging from coded sneezes or pencil tapping to high-pitched noises beyond the hearing range of most teachers. Some students have been known to use more elaborate means, such as using a system of repetitive body signals like hand movements or foot jerking to distribute answers (i.e. where a tap of the foot could correspond to answer "A", two taps for answer "B", and so on). One other method is taking advantage of time zones, particularly in exams administered worldwide. Those who take the exam first (likely in Oceania) can then post answers for those about to take the exam (in a time zone behind like Europe). Impersonation Impersonation is a form of cheating whereby a different person than the student assigned an assignment or exam completes it. Attending a class or completing an interview on another student's behalf is also considered impersonation. The academic work is totally 'outsourced' to another person or organization, usually for pay. Contract cheating Contract cheating, also known as ghostwriting is similar to impersonation in that a student hires a third party to complete work on their behalf. Essay mills fall under this category. While it is believed that contract cheating has significantly increased since 2014, there are currently no figures to demonstrate this surge. This is a relatively new form of cheating, seemingly gaining traction in the 1940s when an increasing amount of advertisements for ghostwriters could be seen on university campuses and in newspapers. This trend continued to grow into the 1960s and 1970s. According to a study conducted in 2019, it is estimated that the ghostwriting industry produces a revenue of approximately $100 million. Plagiarism Plagiarism, as defined in the 1995 Random House Compact Unabridged Dictionary, is the "use or close imitation of the language and thoughts of another author and the representation of them as one's own original work". In academia, this can range from borrowing without attribution a particularly apt phrase, to paraphrasing someone else's original idea without citation, to wholesale contract cheating. The modern concept of plagiarism as immoral and originality as an ideal emerged in Europe only in the 18th century, while in the previous centuries authors and artists were encouraged to "copy the masters as closely as possible" and avoid "unnecessary invention". The 18th century new morals have been institutionalized and enforced