log10Psignal

Log10Psignal is a statistical metric used to express the probability of observing a signal as strong as or stronger than the observed one under a defined null model, using a base-10 logarithm. If Psignal denotes this probability, then log10Psignal equals log10(Psignal). Because Psignal lies between 0 and 1, log10Psignal is always non-positive, and more negative values indicate smaller probabilities and stronger evidence against the null hypothesis. For example, a Psignal of 0.001 corresponds to log10Psignal of -3.

In practical terms, log10Psignal is often used to rank candidate signals and to summarize statistical significance in a compact form. It appears in various fields, including proteomics, genomics, astronomy, and signal processing, wherever a probabilistic assessment of signal detection under noise is needed. Some workflows prefer reporting the negative base-10 logarithm, -log10Psignal, because it yields positive scores that rise with confidence, though this is simply a sign-convention choice and the two representations are equivalent up to a sign.

Computation of log10Psignal typically relies on a null model or distribution for noise, from which Psignal is derived via analytical formulas or empirical estimation (such as permutation testing or simulations). The resulting value is then transformed by the base-10 logarithm. Care should be taken to interpret log10Psignal in light of multiple testing, model assumptions, and calibration; it conveys evidence strength but not effect size.

See also: p-value, -log10 p-value, false discovery rate, multiple testing, statistical significance.