# Reliability Growth Projection

A reliability projection is an assessment of reliability that can be anticipated at some future point in the development program. The projection is based on the achievement to date and engineering assessments of future program characteristics. Projection is a particularly valuable analysis tool when a program is experiencing difficulties because it enables investigation of program alternatives.

## Projection Models

- AMSAA-CROW Projection Model (ACPM)
- AMSAA Discrete Projection Model (ADPM)
- AMSAA Maturity Projection Model (AMPM)

## AMSAA-CROW Projection Model (ACPM)

### Purpose

The purpose of ACPM is to estimate the system reliability at the beginning of a follow-on test phase by taking into consideration the reliability improvement from delayed fixes.

### Benefit

The benefits associated with ACPM include:

- The ability to project the impact of delayed corrective actions on system reliability; and
- The projection takes into account the contribution to the system failure intensity due to unobserved B-modes.

## AMSAA Discrete Projection Model (ADPM)

### Purpose

The purpose of the ADPM is to provide an estimate of the projected reliability following the implementation of both delayed and non-delayed fixes for discrete (one-shot) systems. The model also provides estimates of the following important reliability growth metrics:

- The reliability growth potential;
- Probability of a new failure mode occurring; and
- Fraction surfaced of the system's initial probability of failure.

### Benefit

The benefits associated with ADPM include:

- Corrective actions can be implemented during the test or can be delayed until the end of test;
- Reliability can be projected for future milestones;
- The system's growth potential can be compared to program objectives; and
- The projection takes into account the contribution of the system's probability of failure due to unobserved modes.

## AMSAA Maturity Projection Model (AMPM)

### Purpose

The purpose of AMPM is to provide an estimate of the projected reliability following the implementation of both delayed and non-delayed fixes. The model also provides estimates of the following important reliability growth metrics:

- B-mode initial failure intensity
- expected number of B-modes surfaced
- percent surfaced of the B-mode initial failure intensity surfaced
- rate of occurrence of new B-modes

### Benefit

The benefits associated with AMPM include:

- Corrective actions can be implemented during test or can be delayed until the end of test;
- Reliability can be projected for future milestones;
- The model can project the impact of delayed corrective actions on system reliability;
- The projection takes into account the contribution to the system failure rate due to unobserved B-modes;
- In situations where there is an apparent steepness of cumulative number of B-modes versus cumulative test time over an early portion of testing after which this rate of occurrence slows, there is methodology to partition the early modes from the remaining modes. These early B-modes must be aggressively and effectively corrected.
- Additionally methodology exists to handle cases where there is an early "gap" or if there appears to be a difference in the average FEFs in early or start-up testing versus the remainder of testing (an apparent or visual difference in failure rate in the initial testing).