Quality Progress - March 2017 - 56


A refresher on a quality
tool, concept or method

Shedding
More Light

The scientific method can help
answer difficult questions in
root cause analysis

TA B L E   1

The scientific method
Step

by Matthew Barsalou
The scientific method is used in science; however, it's
also appropriate when performing a root cause analysis.
Using the scientific method can help ensure that the true
cause of a failure is identified. Identifying the cause of a failure is essential because corrective actions will be ineffective
if they are not based on the root cause of the problem.
According to Stephen Tramel, there is no one scientific
method. There are, however, six steps that are commonly
used to test and evaluate the hypotheses (see Table 1).1
The first and last steps are empirical: They are based
on observations by using senses such as touch, hearing
or sight, and perhaps through measuring devices such as
calipers.
Observations are made and data collected during the
first step. Next, data are analyzed. In this example, an
analysis of the data indicates that all failures are occurring on parts produced on night shift. Then you must
generalize beyond the available data to form a hypothesis. In this case, the hypothesis is: "Only parts produced
during the night shift are failing."
The fourth step is assuming the hypothesis is true
for the sake of testing. Next, test results are predicted
based on the assumption that the hypothesis is true. The
hypothesis is tested during this final step. Parts from the
day and night shifts are completely inspected for a week.
Only night-shift parts should have failures if the hypothesis is correct. In this example, there is an approximately
equal number of failures between the two shifts, so the
hypothesis is rejected.
George E.P. Box, Stuart Hunter and William G. Hunter
explain that induction and deduction are used in forming
and evaluating hypotheses.2 To form a hypothesis,

Type of action

Actions

1

Empirical

Make observations and collect data.

2

Conceptual

Analyze the data.

3

Conceptual

Form a hypothesis that extends
beyond the available data.

4

Conceptual

Assume the hypothesis is true for
the sake of testing.

5

Conceptual

Predict what the test results would
be if the hypothesis is true.

6

Empirical

Test the hypothesis.

Source: Stephen Tramel, "Explanatory Hypotheses and the Scientific
Method," Ways of Knowing in Comparative Perspective: The WKCP
Companion and Anthology, Copley Custom Textbooks, 2006.

you start with what is known, including what has been
observed, and any known theories and uses. The hypothesis is tested. If it fails the testing, induction is used to
go from the results to a theory that fits the results, and a
new hypothesis is formed and tested.3
This process can be repeated until a hypothesis is
robust enough to survive testing. Using the earlier
example, you may hypothesize: "The failure occurs at an
equal rate between shifts, but the night shift was better
at detecting the failure."
The root cause still has not been found, but investigators now better understand the issue and are closer to
finding the root cause because they
are no longer examining nonexistent
REFERENCES
variation between shifts.
1. Stephen Tramel,
"Explanatory Hypotheses
The scientific method can help
and the Scientific
answer difficult questions and also
Method," Ways of
can lead to new discoveries. In addiKnowing in Comparative
Perspective: The
tion to be being useful for researchers
WKCP Companion
and scientists, the method can apply
and Anthology, Copley
when investigating a quality failure.
Custom Textbooks, 2006.

Matthew Barsalou is a statistical problem resolution Master Black
Belt (MBB) at BorgWarner Turbo Systems Engineering GmbH in
Kirchheimbolanden, Germany. He has a master's degree in business
administration and engineering from Wilhem Büchner Hoschschule in
Darmstadt, Germany, and a master's degree in liberal studies from Fort
Hays State University in Hays, KS. Barsalou is an ASQ member and holds
several certifications.

56 QP

March 2017 ❘ qualityprogress.com

2. George E.P. Box, Stuart
Hunter and William
G. Hunter, Statistics
for Experimenters: An
Introduction to Design,
Data Analysis and Model
Building, second edition,
John Wiley & Sons, 2005.
3. Ibid.


http://www.qualityprogress.com

Table of Contents for the Digital Edition of Quality Progress - March 2017

Seen and Heard
Expert Answers
Progress Report
Mr. Pareto Head
Field Notes
Innovation Imperative
Hard Wired
Propel Forward
Life After Disruption
Work Smarter, Not Harder
Statistics Spotlight
Standard Issues
Marketplace
Footnotes
Back to Basics
Quality Progress - March 2017 - cover1
Quality Progress - March 2017 - cover2
Quality Progress - March 2017 - 1
Quality Progress - March 2017 - 2
Quality Progress - March 2017 - 3
Quality Progress - March 2017 - 4
Quality Progress - March 2017 - 5
Quality Progress - March 2017 - Seen and Heard
Quality Progress - March 2017 - 7
Quality Progress - March 2017 - Expert Answers
Quality Progress - March 2017 - 9
Quality Progress - March 2017 - Progress Report
Quality Progress - March 2017 - 11
Quality Progress - March 2017 - 12
Quality Progress - March 2017 - Mr. Pareto Head
Quality Progress - March 2017 - Field Notes
Quality Progress - March 2017 - 15
Quality Progress - March 2017 - 16
Quality Progress - March 2017 - 17
Quality Progress - March 2017 - Innovation Imperative
Quality Progress - March 2017 - 19
Quality Progress - March 2017 - 20
Quality Progress - March 2017 - 21
Quality Progress - March 2017 - Hard Wired
Quality Progress - March 2017 - 23
Quality Progress - March 2017 - 24
Quality Progress - March 2017 - 25
Quality Progress - March 2017 - 26
Quality Progress - March 2017 - 27
Quality Progress - March 2017 - Propel Forward
Quality Progress - March 2017 - 29
Quality Progress - March 2017 - 30
Quality Progress - March 2017 - 31
Quality Progress - March 2017 - 32
Quality Progress - March 2017 - 33
Quality Progress - March 2017 - Life After Disruption
Quality Progress - March 2017 - 35
Quality Progress - March 2017 - 36
Quality Progress - March 2017 - 37
Quality Progress - March 2017 - 38
Quality Progress - March 2017 - 39
Quality Progress - March 2017 - Work Smarter, Not Harder
Quality Progress - March 2017 - 41
Quality Progress - March 2017 - 42
Quality Progress - March 2017 - 43
Quality Progress - March 2017 - Statistics Spotlight
Quality Progress - March 2017 - 45
Quality Progress - March 2017 - 46
Quality Progress - March 2017 - 47
Quality Progress - March 2017 - Standard Issues
Quality Progress - March 2017 - 49
Quality Progress - March 2017 - Marketplace
Quality Progress - March 2017 - 51
Quality Progress - March 2017 - Footnotes
Quality Progress - March 2017 - 53
Quality Progress - March 2017 - 54
Quality Progress - March 2017 - 55
Quality Progress - March 2017 - Back to Basics
Quality Progress - March 2017 - cover3
Quality Progress - March 2017 - cover4
https://www.nxtbook.com/naylor/ASQM/ASQM0719
https://www.nxtbook.com/naylor/ASQM/ASQM0619
https://www.nxtbook.com/naylor/ASQM/ASQM0519
https://www.nxtbook.com/naylor/ASQM/ASQM0419
https://www.nxtbook.com/naylor/ASQM/ASQM0319
https://www.nxtbook.com/naylor/ASQM/ASQM0219
https://www.nxtbook.com/naylor/ASQM/ASQM0119
https://www.nxtbook.com/naylor/ASQM/ASQM1218
https://www.nxtbook.com/naylor/ASQM/ASQM1118
https://www.nxtbook.com/naylor/ASQM/ASQM1018
https://www.nxtbook.com/naylor/ASQM/ASQM0918
https://www.nxtbook.com/naylor/ASQM/ASQM0818
https://www.nxtbook.com/naylor/ASQM/ASQM0718
https://www.nxtbook.com/naylor/ASQM/ASQM0618
https://www.nxtbook.com/naylor/ASQM/ASQM0518
https://www.nxtbook.com/naylor/ASQM/ASQM0418
https://www.nxtbook.com/naylor/ASQM/ASQM0318
https://www.nxtbook.com/naylor/ASQM/ASQM0218
https://www.nxtbook.com/naylor/ASQM/ASQM0118
https://www.nxtbook.com/naylor/ASQM/ASQM1217
https://www.nxtbook.com/naylor/ASQM/ASQM1117
https://www.nxtbook.com/naylor/ASQM/ASQM1017
https://www.nxtbook.com/naylor/ASQM/ASQM0917
https://www.nxtbook.com/naylor/ASQM/ASQM0817
https://www.nxtbook.com/naylor/ASQM/ASQM0717
https://www.nxtbook.com/naylor/ASQM/ASQM0617
https://www.nxtbook.com/naylor/ASQM/ASQM0517
https://www.nxtbook.com/naylor/ASQM/ASQM0417
https://www.nxtbook.com/naylor/ASQM/ASQC12518
https://www.nxtbook.com/naylor/ASQM/ASQM0317
https://www.nxtbook.com/naylor/ASQM/ASQM0217
https://www.nxtbook.com/naylor/ASQM/ASQM0117
https://www.nxtbook.com/naylor/ASQM/ASQM1216
https://www.nxtbook.com/naylor/ASQM/ASQM1116
https://www.nxtbook.com/naylor/ASQM/ASQM1016
https://www.nxtbook.com/naylor/ASQM/ASAC0016
https://www.nxtbook.com/naylor/ASQM/ASQM0916
https://www.nxtbook.com/naylor/ASQM/ASQA0016
https://www.nxtbook.com/naylor/ASQM/ASQM0816
https://www.nxtbook.com/naylor/ASQM/ASQM0716
https://www.nxtbook.com/naylor/ASQM/ASQM0616
https://www.nxtbook.com/naylor/ASQM/ASQM0516
https://www.nxtbook.com/naylor/ASQM/ASQM0416
https://www.nxtbook.com/naylor/ASQM/ASQM0316
https://www.nxtbook.com/naylor/ASQM/ASQM0216
https://www.nxtbook.com/naylor/ASQM/ASQM0116
https://www.nxtbook.com/naylor/ASQM/ASQM1215
https://www.nxtbook.com/naylor/ASQM/ASQM1115
https://www.nxtbook.com/naylor/ASQM/ASQM1015
https://www.nxtbook.com/naylor/ASQM/ASQM0915
https://www.nxtbook.com/naylor/ASQM/ASQM0815
https://www.nxtbook.com/naylor/ASQM/ASQM0715
https://www.nxtbook.com/naylor/ASQM/ASQM0615
https://www.nxtbook.com/naylor/ASQM/ASQM0515
https://www.nxtbook.com/naylor/ASQM/ASQM0315
https://www.nxtbook.com/naylor/ASQM/ASQM0215
https://www.nxtbook.com/naylor/ASQM/ASQM0115
https://www.nxtbook.com/naylor/ASQM/ASQM1214
https://www.nxtbook.com/naylor/ASQM/ASQM1114
https://www.nxtbook.com/naylor/ASQM/ASQM1014
https://www.nxtbook.com/naylor/ASQM/ASQM0914
https://www.nxtbook.com/naylor/ASQM/ASQM0814
https://www.nxtbook.com/naylor/ASQM/ASQM0714
https://www.nxtbook.com/naylor/ASQM/ASQM0614
https://www.nxtbook.com/naylor/ASQM/ASQM0514
https://www.nxtbook.com/naylor/ASQM/ASQM0414
https://www.nxtbook.com/naylor/ASQM/ASQM0314
https://www.nxtbook.com/naylor/ASQM/ASQM0214
https://www.nxtbook.com/naylor/ASQM/ASQM0114
https://www.nxtbook.com/naylor/ASQM/ASQM1213
https://www.nxtbook.com/naylor/ASQM/ASQM1113
https://www.nxtbook.com/naylor/ASQM/ASQM1013
https://www.nxtbook.com/naylor/ASQM/ASQM0913
https://www.nxtbook.com/naylor/ASQM/ASQM0813
https://www.nxtbook.com/naylor/ASQM/ASQM0713
https://www.nxtbook.com/naylor/ASQM/ASQM0613
https://www.nxtbook.com/naylor/ASQM/ASQM0513
https://www.nxtbook.com/naylor/ASQM/ASQM0413
https://www.nxtbook.com/naylor/ASQM/ASQM0313
https://www.nxtbook.com/nxtbooks/naylor/ASQM0213
https://www.nxtbook.com/nxtbooks/naylor/ASQM0113
https://www.nxtbook.com/nxtbooks/naylor/ASQM1212
https://www.nxtbook.com/nxtbooks/naylor/ASQM1112
https://www.nxtbook.com/nxtbooks/naylor/ASQM1012
https://www.nxtbook.com/nxtbooks/naylor/ASQM0912
https://www.nxtbookmedia.com