The single salary schedule that has been prevailing in American public education for long has been criticized a lot. Also, the advent of value-added assessment has demolished the technical excuses for stonewalling merit pay. Different merit pay schemes are being implemented in some districts in America,such as the Romney plan,the Milken Family Foundation's Teacher Advancement Program and the Tennessee teacher reward program. Merit pay has become a key component of comprehensive education reform aimed ...
长期以来在美国公立学校占统治地位的单一工资制近些年来受到了许多批评,随着“增值评估”的出现,影响绩效工资实施的技术障碍似已不复存在,绩效工资制度改革在美国一些地区的公立学校中正深入开展,以激励教师与提高学生成绩为宗旨的绩效工资已经成为美国全面教育改革的重要组成部分。典型案例包括罗蒙内计划、米尔肯家庭基金会的教师提升项目、田纳西州查塔努加的教师奖励方案等。改革目前虽遭受很大的阻力,但受到了两党的支持,具有广阔的发展前景。

这个词如果直译的话，会感觉很别扭。其具体意思Wenjer兄已解释，此处仅给出另一意译方式。
具体英文解释可参阅链接中PDF文件中的说明，打开该文件后，在查找栏内直接键入“stonewalling”，用不了几次即可查到整个句子。