failureratio

Failureratio is a measurement used in reliability engineering, quality assurance, and data analysis to quantify the proportion of unsuccessful outcomes in a defined set of trials. It is defined as the number of failures divided by the total number of trials or observations. The value ranges from 0 to 1 (or 0% to 100%). In many contexts it approximates the probability that a given trial ends in failure, assuming the trials are representative and independent.

Calculating failureratio is straightforward: failureratio = failures / total_trials. It can be applied to manufacturing batches, software test runs, or experimental measurements. For example, in a batch of 100 LED units, if 4 fail during screening, the failureratio is 0.04 or 4%. The metric is useful for tracking quality over time and for comparing different processes or configurations, but it should be complemented by other statistics such as confidence intervals, control charts, or time-to-failure analyses.

Limitations include sensitivity to sample size and selection bias, lack of information about failure timing, and potential misinterpretation when the process evolves over time. Failureratio does not capture rate dynamics unless defined over a moving window or time period. Related concepts include defect rate, failure rate, success rate, and hazard rate.

See also reliability, quality control, defect rate, failure rate, and mean time between failures.