90 percent of performance appraisal processes are inadequate. Why?

I think you should manipulate the percentage to40-60%, my point of view, that there's no strategy for the importance of such issue for several criteria( training,salary increments,,,, job opportunities within Organization ),&I agree with you that there's no support from top management.

Most of the assessment that managers complete focuses on “the person,” including characterizations of their personal “traits” (i.e. commitment), knowledge (i.e. technical knowledge) or behaviors (i.e. attendance). While these factors may contribute to performance, they are not measures of actual output. If you want to assess the person, call it “person appraisal.” Performance is output quality, volume, dollar value, and responsiveness.

many accept that the goals of the process are to recognize results, provide feedback to address weaknesses, determine training needs, and to identify poor performers. Unfortunately, rarely do process owners ever measure their processes’ contribution to attaining any of these goals. Instead, the most common measure relating to performance appraisal is the percentage completed.

Lack of support from top management in terms of Performance Appraisal.