Scholarly overview of casting lots in Eerdmans Dictionary of the Bible.
Julye Bidmead, "Lots," in Eerdmans Dictionary of the Bible, ed. David Noel Freedman (Grand Rapids, Michigan: Eerdmans, 2000), 825
LOTS
Objects cast to determine an answer beyond human comprehension or to make a decision requiring divine guidance . . . Lots were presumably small stones or pieces of wood and are always referred to as being thrown, shaken, or cast down. The practice of lot casting is connected with the Urim and Thummim, priestly oracle devices which may have also been lots or small dice.
. . . The divinatory technique termed psephomancy or cleromancy refers to lot casting, a prevalent method of divination in the ancient world. In the Bible, however, the casting of lots was one of the few legitimate means of divine revelation (as were dreams and direct communication with the deity). Lot casting is not among the condemned mantic or divinatory practices such as soothsaying, magic, and necromancy (cf. Deut. 18:10-12). Lot casting, therefore, had divine sanction and control. Though the throwing of the lots was a human action, the revelation was a direct message from God (Prov. 16:33).