Log likelihood

Introduction

When evidence is entered in a Bayesian network or Dynamic Bayesian network, the Probability (likelihood) of that evidence, denoted P(e) can be calculated.

The Probability of evidence P(e) indicates how likely it is that the network could have generated that data. The lower the value, the less likely.

Log likelihood user interface

Note: The Log Likelihood Log(P(e)) is also reported, as the P(e) can often report zero, due to underflow caused by the repeated multiplication of small probability values, using floating point arithmetic.

An example of zero likelihood:

Zero likelihood

Note: Log Likelihood values are often used to detect anomalous data.