Tree Analysis Approach for Variation Reduction of Product Characteristics

A tree analysis method was developed for strategically and objectively reducing the variation of product characteristics. The additive property of variances makes it possible to divide the resulting variance of a product characteristic into the responsible basic component variances (or common causes of variation). Combining this property with a tree diagram results in an approach which produces a quantitative representation of each component's contribution to the overall output variation. The quantitative data, obtained from relevant individual experiments, will show where efforts must be concentrated in order to significantly reduce the output variation.