Metrics
The Covering Array Metrics section gives you information about how well the design meets the strength requirements. See Dalal and Mallows (1998) for background on these metrics for unconstrained designs.
t
The number of factors.
Coverage
The ratio of the number of distinct t-factor settings that appear in the design to the total possible number of t-factor settings, expressed as a percentage. A t-coverage of 100% indicates that all possible t-factor settings are covered by the design. Note that each t-factor setting can appear multiple times.
For constrained and unsatisfiable designs, the definition of Coverage is adjusted for the number of t-factor settings that are possible once the constraints have been applied to all t-factor combinations. See Formulas for Metrics.
Diversity
The ratio of the number of distinct t-factor settings in the design to the total number of occurrences of t-factor settings in the design, expressed as a percentage. The t-diversity measures how well the design avoids replication. A t-diversity of 100% indicates that no t-factor settings are repeated. A t-diversity of 50% indicates that the average number of times that distinct t-factor settings appear is two.
For constrained and unsatisfiable designs, the definition of Diversity is adjusted for the number of runs with missing settings. See Formulas for Metrics.