This article compares the small-sample properties of the Agresti-Pendergast and the ATS rank-based method, as described in Brunner, Domh, and Langer (2002), for comparing J dependent groups. The results indicate that the Type I error of the Agresti-Pendergast method is more conservative when J = 2 , but under most conditions, the ATS method performs best in terms of both Type I errors and power.
Tian, Tian and Wilcox, Rand R.
"A Comparison of Two Rank Tests for Repeated Measure Designs,"
Journal of Modern Applied Statistical Methods: Vol. 6
, Article 31.
Available at: http://digitalcommons.wayne.edu/jmasm/vol6/iss1/31