For instance, in the case of a random match, if five genetic components are analyzed and we have two individuals identified, we need to look at additional genetic components. The greater the number tested the easier it is to discriminate between two individuals. Two individuals may possess five identical genetic components but by looking at a number of other components, it is possible to distinguish between the two.
Therefore, the greater the number of loci analyzed, and some are identical in 13 loci, for instance, the closer we get, through statistical calculations, to a profile fitting these 13 loci, which would be one person out of 600 billion which could possess these 13 identical genetic loci.
You can determine frequency, within the population... It is very rare to find an individual with the same profile as another. When looking at five genetic loci, there could be one out of three million individuals, for instance, who could have a corresponding profile. If we analyze additional genetic loci, we can discriminate further.
Technology evolves, we do an increasing number of genetic loci, and we arrive at results which allow us to discriminate with near certainty between two individuals.