In Circuit Test Fixture Coverage and Unprobed Assembly Netlist Limits
Unprobed netlists drop structural fault coverage, requiring integrated boundary scan vectors and adjusted warranty reserves to cover escape risks.
Functional Test Catch Rate
Detection Efficiency
Quality control in electronics manufacturing relies on a metric that measures the proportion of defective printed circuit board assemblies detected during final operational evaluation. Calculated at the end of the assembly line, functional test catch rate reveals how well the functional test suite detects errors that escaped prior optical, solder paste, and in-circuit inspections. A low rate indicates that many assembly faults or component failures are passing through undetected to the next stage of integration or to the customer.
This percentage helps engineers identify weaknesses in the test coverage or test program execution.
Calculation Method
Tracking this metric requires comparing the faults found during the test against the faults discovered in subsequent field use or system-level integration. In practice, the functional test catch rate is expressed as the number of confirmed test failures divided by the sum of those failures plus any escape failures returned from later stages. Accurate classification of returns is necessary to ensure that only manufacturing defects and not user-induced damage are included in the math.
This tracking helps the plant balance the cost of test development against the risk of escaping defects.
Process Influence
Test coverage limits the maximum possible value of this metric. If the test program does not exercise a specific circuit branch, functional test catch rate for that fault category remains zero.