the concentration is calculated based on the fraction of droplets that is empty (that is, the fraction that does not contain any target DNA).

There is a simple mathematical relationship between the fraction of droplets that are unoccupied (black bar) and the concentration of target molecules.

Some droplets are lost in transfer steps and others are eliminated by the stringent metrics applied by QuantaSoft Software as the droplets pass through the Droplet Reader, resulting ultimately in data from 12,000–16,000 droplets being used in subsequent concentration calculations

Partitioning the sample into small containers results in a statistical distribu-tion of targets

purifying the target of interest from interfering compounds.