# Statistical Tolerance Analysis--A Survey on Awareness, Use and Need in German Industry
## 6 Current Use of Statistical Tolerance Analysis  
To date, the use of statistical tolerance simulations is by far a self-evident and established step in the German mechanical industry. Nevertheless, surprisingly, many companies (42 of 101, 1 abstention) were already making efforts to implement tolerance engineering, such as performing statistical tolerance analyses during product development in order to deal with deviations and thus to quantify their effects on the final product. It is not surprising that this ratio was particularly high among participants who worked in \"research and development\". There, 7 out of 9 employees carried out statistical tolerance analyses regularly to evaluate and ensure product quality. In consequence, one may assume that there is a strong correlation between existing knowledge on tolerancing and the companies striving towards the implementation of adequate methods and tools during product development. The following cross table (Figure 5) details the results of two corresponding questions to assess this potential correlation. The cross-evaluation proved that a direct correlation exists between the existence of certain knowledge of the basics of statistical tolerance analysis and its application during product development. The knowledge of statistical tolerance simulations was very low in companies that did not perform tolerance analyses (\(\sim\)19.2% = 10 of 52). In contrast, the majority of the 49 respondents (\(\sim\)65.3% = 32 of 49) whose companies performed statistical tolerance analysis were also familiar with the fundamentals of tolerancing and tolerance analysis. Hence, a strong correlation is obvious and undisputed. Furthermore, it can be concluded that employees (\(\sim\)51.5% = 52 vs. 49) are mostly confronted with statistical tolerance analysis for the first time when already working in German companies and thus years (or even decades) after graduating from university. This indicates a strong lack of lectures and seminars on tolerance engineering in the curricula at universities. Further considering the fact that only one in seven engineers in Germany is of a foreign nationality [60], the cause is actually attributed to the limited extent of lectures and seminars on tolerance engineering, specifically among German universities. Figure 5: Cross-evaluation of the response of 101 participants to the (single-choice) question: “Are you familiar with the basics of statistical tolerance analysis?” and the (single-choice) question: “Does your company make any efforts (such as tolerance analyses) to take account of deviations in products?”. A closer look at the distribution of the participants' departments further revealed that the fundamentals of tolerancing and statistical tolerance analysis were most widespread among engineers who assigned themselves to \"research and development\" as well as among participants from \"management\" (11 of 16). Further, almost every second employee from the remaining departments (engineering design (23 of 53), manufacturing (3 of 8) and quality management (5 of 11) was familiar with the fundamentals of tolerancing and statistical tolerance analysis. This rebuts a frequently given argument that professional expertise on tolerancing is exclusively present in the design department. Furthermore, it clarifies that (as a good approximation) about 50% of all engineers have adequate knowledge of the fundamentals of tolerancing as well as of statistical tolerance analysis--and this is across all departments. Despite the pleasingly high ratio of engineers with proper knowledge of tolerancing among all departments, there was a strong consensus among the survey participants that the analysis and optimization of tolerance specifications are the responsibility of design engineers, who also shared this opinion. However, still not all design engineers performed tolerance analyses during their daily work.