Contemporary slavery, also sometimes known as modern slavery or neo-slavery, refers to institutional slavery that continues to occur in present-day society. Estimates of the number of enslaved people today range from around 38 million to 49.6 million, depending on the method used to form the estimate and the definition of slavery being used. The estimated number of enslaved people is debated, as there is no universally agreed definition of modern slavery; those in slavery are often difficult to identify, and adequate statistics are often not available.