# Statistical Tolerance Analysis--A Survey on Awareness, Use and Need in German Industry
## 7 Need and Potential of Statistical Tolerance Analysis  
An overwhelming majority of 81.4% (=79 of 97; 5 abstention) of the respondents agreed that the additional expenditure arising from establishing and performing statistical tolerance analyses was less than the additional expenditure arising from tolerance-related problems. This is particularly pleasing, since 54.4% of those (=43 of 79) had not yet carried out a tolerance analysis by themselves. This, therefore, showed that, even in companies that had not yet carried out a tolerance analysis, the benefits were already assessed as positive. It is, therefore, not surprising that participants stated that an average of ~30.3% of complications and problems that appeared during the manufacturing, assembly and use of their products could be avoided if statistical tolerance analyses were carried out early on during design. This value even increased to ~40.5% when taking into account only those respondents who already performed tolerance analyses. In addition, ~72.7% of the participating managing directors (=8 of 11), who were familiar with the basic methods of tolerance analysis, stated that the additional workload (to perform statistical tolerance analyses) was less than the workload that would result later from having to solve the unidentified tolerance-related problems. This value increased to 100% when the (seven) managing directors whose companies already carried out tolerance analyses were taken into account. In other words, all the managing directors who supported and/or had introduced tolerance analysis in their companies gained positive experiences and stated that tolerance engineering was key to company success. Furthermore, these seven managing directors stated that ~41.8% of the critical issues during manufacturing, assembly and use were caused by tolerance-related problems. This evaluation was nearly  
Figure 6: Response of 28 participants to the (multiple-choice) question: “Why does your company not make any efforts not make any efforts (such as tolerance analyses) to take account of deviations in products?” (multiple answers were allowed). identical to the answers given by the participating design engineers. Based on these findings, we go so far as to postulate that the positive benefits of statistical tolerance analysis have been recognized and appreciated in German companies across different levels of the corporate hierarchy. This stands in contrast to the common complaint among researchers and industrial experts on tolerance engineering that tolerance analysis is not given the importance and resources it warrants by higher management. However, the authors are aware that the survey only provides one snapshot of a very limited selection of companies. It is, therefore, not surprising that there was a clear interest among 98 respondents (4 abstentions) in learning the basics or deepening their knowledge of statistical tolerance analysis (see Figure 7a). Of these, 29 of the 50 respondents who were not familiar with the basics of statistical tolerance analysis stated a high interest. Nevertheless, even those who already knew the basics of statistical tolerance analysis were interested in expanding their knowledge further. Meanwhile, 21 of these 50 respondents already considered their current knowledge on statistical tolerance analysis to be sufficient to apply in everyday work. However, for sustainable and established tolerance engineering, it is essential to integrate tolerance analysis and tolerance synthesis into existing product development processes and milestone evaluations. When asked about opportunities for improvement in their companies, one respondent demanded the \"firm integration of tolerance analyses into the development process\", in order to be able to \"perform tolerance analysis early\", according to another participant. In addition, a production engineer requested \"to be involved in projects as early as the design stage in order to influence tolerances at an early stage\".