Variants of Levene’s and O’Brien’s procedures not investigated by Keselman, Wilcox & Algina (2008) were examined. Simulations indicate that a new O’Brien variant provides very good Type I error control and is simpler for applied researchers to compute than the method recommended by Keselman, et al.
Othman, Abdul R.; Yan, The Sin; Keselman, H. J.; Wilcox, Rand R.; and Algina, James
"Robust Modifications of the Levene and O’Brien Tests for Spread,"
Journal of Modern Applied Statistical Methods: Vol. 11
, Article 5.
Available at: http://digitalcommons.wayne.edu/jmasm/vol11/iss1/5