Go/no go

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In general go/no go testing refers to a pass/fail test (or check) principle using two boundary conditions. The test is passed only when the Go condition is met and also the No go condition fails.

The test gives no information as to the degree of conformance to, or deviation from the boundary conditions. These tests can be used for statistical process control purposes. There are specific SPC tools that use parameter based measurements (e.g., P-charts) for determining the stability of a process.

In engineering the test is traditionally used only to check noncritical parameters where the manufacturing process is believed to be stable and well controlled, and the tolerances are wide compared to the distribution of the parameter. For example, the preceding checks before a space shuttle liftoff have the flight controller performing a go/no go check on each of the vehicle's critical systems.

In psychology Go/No-go tests are used to measure a participant's capacity for sustained attention and response control. For example, a go/no-go test that requires a participant to perform an action given certain stimuli (e.g., press a button - Go) and inhibit that action under a different set of stimuli (e.g., not press that same button - No-Go).

In the United States Army, drills and proficiency evaluation rubrics are based on a GO/NO GO (pass/fail) system. Evaluations involving numerical scores (such as the Physical Fitness Test) convert raw scores to GO/NO GO based on cutoffs defined by the particular performance standard for that area. Within a given skills unit, the rubric often specifies GO/NO GO scoring for each individual item or concept a soldier is expected to be trained and evaluated on. Usually, a soldier must score GO (i.e. perform satisfactorily) on all sections of an evaluation in order to advance to the next phase of training, to pass the course, and/or to attain the particular qualification.

Go/no go gauges[edit]

Go/no go gauges are encountered in all types of manufacturing. They may measure a physical dimension, e.g. (50 ±0.01mm), or a value such as the value of a resistor (100Ω (ohms) ±1%). A typical example is a plug gauge.

A typical gauge used when making tennis balls would have two holes, one slightly larger than the other. A manufactured object passes the go/no go test if it goes through the large hole but does not go through the smaller hole; the object fails if it passes through the smaller hole, or does not pass through the large hole.