an investigation of the structural change in urban iranian consumers’ preferences for tea using nonparametric revealed preference test

stability and structural change of iranian consumers' preference for tea commodities during 1988-2005 is investigated throughout the coarse of this study. to this end, nonparametric test of revealed preference has been utilized. results of weak axiom of revealed preference (warp) show that in 1995 a contradiction has been in observed consumers' preference for tea with the null hypothesis of preference stability being rejected. the calculated k-w statistic supports the notion that the revealed warp violation is not a transitory shock, but caused by a permanent structural change in consumers’ preferences. . . . . . . . . . .