p99
p99, commonly written as p99, refers to the 99th percentile in statistics. It is the value below which 99 percent of observations in a data set fall. The 99th percentile is a type of quantile and helps describe tail behavior of a distribution, providing insight into worst-case performance or extreme values. Different methods exist for computing percentile values, including nearest-rank and linear interpolation between order statistics. In practice, p99 is estimated from samples by sorting values and selecting the appropriate rank, or by using quantile estimators for large or streaming data. It is often reported alongside other percentiles such as p95 and p50 in performance analysis, quality control, and risk assessment.
Project 1999, often abbreviated p1999 or p99 in community discussions, is a community-driven open-source project that
In computing and performance contexts, p99 latency refers to the 99th percentile of observed response times