TS EN 61164

TS EN 61164 is the standard for statistical test and estimation methods used to assess reliability growth from failure data collected during a reliability improvement programme. Reliability growth is the quantified tracking of how failure behaviour improves as a product or system is developed, so the document supports numerical interpretation of change rather than simple observation of defect trends.

Statistical framework for reliability growth

According to its scope, the standard addresses the construction of growth models from failure records generated during improvement activities, the estimation of product reliability, confidence intervals, and goodness-of-fit tests. In practice, this means failure data can be used to measure the effect of design changes, corrective actions, or process improvements on expected performance. The approach makes it possible to study development trends over time in a way that is more informative than a single failure count.

Where the standard is used and what it distinguishes

• These methods are commonly used to monitor reliability targets during development, verification, and field-feedback stages.
• Reliability growth does not merely describe the current failure rate; it aims to quantify the effect of improvement work.
• Statistical tests and estimation methods help evaluate how well a model fits the data and how much uncertainty surrounds the result.

In general technical context, the value of this standard is its ability to support a consistent and comparable analysis of different failure-data sets. It helps engineers interpret reliability development more coherently, separate trends from noise, and assess the effect of improvement programmes in numerical terms.