We detect a cheating strategy used in Massive Open Online Courses (MOOCs).
We call this strategy, “Copying Answers using Multiple Existences Online” (CAMEO).
We estimate conservatively that at least 1.3% of certificates were earned by CAMEO.
Among earners of 20 or more certificates, 25% have used the CAMEO strategy.
CAMEO represents one of many threats to the validity of MOOC certifications.