Would you believe you don't need life data?

Reliability Decision-Making Flowchart

Introduction to this web site

Reliability Decision-Making Flowchart

This a pseudo-program that implements a flowchart...

1. Do I want to know my products' and parts' age-specific field reliability?
  1. No thanks, ignorance is bliss
  2. Yes, field reliability is fundamental to our business and to our suppliers' and our customers' businesses.
2. Do I have to track products and parts by name and serial number to get their ages-at-failures and survivors' age?

- 1. Yes.
    1. The FAA requires tracking of ~75 safety-critical system by tail number and serial number.
    2. The NIH and CDC require "Universal Device Identifier" for all lFDA act 201(h) medical devices.
    3. Automotive OEMs track using www.reyrey.com under warranty. At least 3 Oracle-based service dbs do it by part name, although they don't distinguish whether multiple failures of same part name were first failure of second part or second failure of first part.
  2. No.

- - 1. Ships and returns counts are statistically sufficient to make nonparametric estimates of age-specific field reliability and failure rate functions for products and their parts.
    2. For parts, you need BoMs to convert product installed base into part installed base using the gozinto matrix of parts per product or next assembly.

1. Do I want to buy a mainframe computer or a cloud; major service db, AI data-mining software, and reliability statistics programs, and employ many people tediously keeping records, making data entries, getting bored, and entering errors; and learning field reliability only for tracked parts using possibly incorrect assumptions built into the reliability software?

- 1. Yes, it's good for the economy
    1. Do you need help justifying assumptions built into reliability statistical software? See How to Make Data Fit Weibull? "Verification and Validation of Alternative Facts."
    2. Or would you like a constant failure rate = 1/MTBF?
  2. No. I prefer to send installed base and field reliability data to pstlarry077@gmail.com, describe it, and ask questions, at least to see whether nonparametric, age-specific field reliability and failure rate function estimates, without life data, (from data required by GAAP) are good enough. How much bang-per-buck do you get for information from life data vs. essentially free reliability information

1. What if failures are dependent: successive failures or repairable systems or failures of parts within same system (e. g. Tesla Model S battery, charger, and drive unit)? Make nonparametric, multivariate distribution estimates of TTFF, TBF1, TBF2...

- 1. Are you kidding? We assume independence and fudge forecasts if they don't agree with observations.
  2. Wow. Can I do that even if I don't have life data TBFs for repairable systems? Yes, send your data to psltarry077@gmail.com.

If you would like comparisons of field reliability estimates, with vs. without life data, ask for "Random-Tandem Queues and Field Reliability Estimation, Without Life Data" now on this site

Introduction to this web site

Google updated this web site Jan. 13, 2022. Please contact me if you want articles and files: pstlarry077@gmail.com.

Software

Please let me know if you want these or send data to pstlarry077@gmail.com.

Estimate field reliability, without life data, dead-forever or repairable systems or parts

Make actuarial forecasts and estimate prediction limits for stock level recommendations

Correct homophone errors "Yeltsin Eeks Out Victory" local newspaper. "Stocks Eek out Gains," Yahoo Finance, Dec. 27, 2019

MTBF with redundancy

Multivariate P[g(Stress, strength)=failure | Eq] old

Design and Analysis of Accelerated Reliability Tests

Publications

Recent pubs

"Random-Tandem Queues and Reliability Estimations, WIthout Life Data" https://sites.google.com/site/fieldreliability/random-tandem-queues-and-reliability-estimation-without-life-data/

Credible Reliability Prediction, second Edition, link...

https://sites.google.com/site/fieldreliability/credible-reliability-prediction/

Fred Schenkelberg, https://accendoreliability.com/, invited me to give Credible Reliability Prediction as a webinar at Hewlett-Packard. Please refer to www.AccendoReliability.com for anything you want to know related to reliability. Fred is publishing some of my articles in a series on Reliability Statisitcs. Fred and his associates have been doing more than any one person could possibly do.

"User Manual for Credible Reliability Prediction"

https://sites.google.com/site/fieldreliability/user-manual-for-credible-reliability-prediction/

Design ALT Newer!

Opportunistic Replacement Old!

Work (Ask for articles that don't have links!)

Firestone tire reliability. Firestone could have known in '97

Reliability is Free!

Evaluate field reliability applications

Fables of automotive reliability

Virtual reliability?

Virtual statistics? Cheat!

Newsletters Links work