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Sample Size Considerations in Probability of Detection Studies for Nondestructive Evaluation

Christine Schubert Kabban Co-Author
Air Force Institute of Technology
 
Ray de Asis First Author
 
Ray de Asis Presenting Author
 
Wednesday, Aug 6: 9:50 AM - 10:05 AM
2560 
Contributed Papers 
Music City Center 
The United States Air Force utilizes methodologies in MIL-HDBK-1823A as a standard to enable Probability of Detection (POD) studies for Nondestructive Evaluation, as means to aid the evaluation of airframe integrity. The primary metric of interest in these studies is the upper bound of the 95% confidence interval associated with the 0.90 POD, also known as a90|95, the largest detectable flaw size for this probability. Therefore, to estimate a90|95, data is collected across a wide range of flaw sizes in order to build a curve with enough fidelity to estimate this bound. As such, sample size becomes an important consideration in these studies due to the associated cost and required resources. This work examines current and extended contemporary methods for POD estimation with respect to sample size requirements. Specifically, we present and compare formulas for POD estimation utilizing one methodology outlined in MIL-HDBK-1823A: 1) a vs a-hat, in addition to 2) methods for dependent data. We conclude by comparing sample size requirements for these methods across a range of data characteristics inspired by typical POD studies.

Keywords

Probability of Detection

Nondestructive Evaluation

flaw size

a-hat vs a

hit/miss

sample size 

Main Sponsor

Section on Statistics in Defense and National Security