A blog post by Hugo Landau argues that a 98% success rate is often insufficient in practice, using the analogy of cleaning up pine needles to illustrate how even a tiny remaining mess can render the effort unacceptable. The post challenges the common assumption that high percentages are sufficient, highlighting that context matters greatly in determining acceptable thresholds, which is crucial for software reliability, quality assurance, and risk assessment. The author uses the example of removing 99% of pine needles—while numerically impressive, the remaining 1% is still visually distinct and unacceptable. The post also points out that percentages can be misleading near their extremes, where a change from 98% to 99% cuts the failure rate in half.
Background
Percentages are commonly used to measure success rates, but they can obscure the practical significance of failures. For example, a 99.9% uptime still means significant downtime over a year for critical systems. The blog post explores this idea with everyday analogies.
Discussion
Comments generally agree with the premise but add nuance: some argue that 98% is sufficient in business contexts, while others reinforce that percentages can be deceptive and that small failure rates compound in large systems. A notable comment from nemo1618 uses the pine needle analogy to support the post's view.