Denis F. Cioffi, Ph.D. 20 November 2016
Senior Advisor to the Dean School of Business
Associate Professor (via courtesy) Physics Department
The George Washington University firstname.lastname@example.org
Assignment 14 (10 per cent of total grade)
Due Wednesday 7 December 2016
MBAd6224, Decision Making and Data Analysis
This assignment asks you to address questions about statistical evidence for truth. In
common with the previous written assignment, the topics to be addressed stem from another
provocative article, Why Most Published Research Findings Are False. (As usual, everything
in blue is a link.) After you read the paper itself, I recommend reading the comments about
it that follow.
1 Possible Additional Readings
Although the assignment can be completed by reading only the subject paper, you may be
interested in knowing that repeated occurrences of non-reproducible results has generated
much recent discussion about this general problem of statistical inference. I have referenced
most of these papers already in the Enjoy Reading file and on the open MBAd6224 open
website. I note several in particular:
? ?How can so many scientists have been so wrong?? asked Engber in Slate magazine
? In response, Sanjay Srivastava, a psychology professor at the University of Oregon,
created a fictitious course in which Ioannidis?s paper is discussed in Week 8, about
? ?How scientists fool themselves … ?
? The concerns are so high that in June the American Statistical Association published a
paper, The ASA?s statement on p-values: context, process, and purpose.
Dr. Denis F. Cioffi 224 Fall 2016
2 The Assignment Itself
I have divided this assignment into two halves. As described immediately below, the first is
an explanation of the paper itself, and the second is a reaction to it.
1. Part 1 [50 points]. Explain the basics of the paper. The first three items are mandatory,
but I have also listed a few other topics as additional possibilities to address in your
a. (Mandatory [8 points].) Using the definition of R, explain in a couple of sentences
why ?The pre-study probability of a relationship being true is R/(R + 1).?
b. (Mandatory [8 points].) Explain ?Positive Predictive Value,? PPV.
c. (Mandatory [8 points].) Discuss the author?s notion of bias.
i. You might relate it to any of the homework assignment problems, which were
largely sterile in that regard. Or not.
d. We have lately focused on p values, so you might comment upon the statement,
?Research is not most appropriately represented and summarized by p-values, but,
unfortunately, there is a widespread notion that medical research articles should
be interpreted based only on p-values.?
e. We would prefer remaining naive and not considering Corollary 5, but we must
accept its reality. (Mustn?t we?)
f. ?Empirical evidence on expert opinion shows that it is extremely unreliable.?
g. We have only perceived single-team studies for the homework assignments, but
the author writes, ?… it is misleading to emphasize the statistically significant
findings of any single team.?
Unlike last time, some answers now can be factually wrong: if you do not properly
explain the parts of the paper that are to be addressed specifically (above), you will
2. Part 2 [50 points]. Now that you have explained the paper?s fundamentals, turn and
discuss what it might mean to your worldview by addressing two of the following [25
a. Again we compare to the business world. Explain if the problems noted by this
author have the same potential for harming statistical data analysis in business as
they do in science. (Hint: the answer is ?yes.?) How should they be addressed?
b. How does one live as an individual in such an uncertain world? For example, how
do you react now to studies you hear about, especially ones that suggest changing
the way you live for health reasons?
c. What is your personal solution to the analysis of data for which you might be
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Dr. Denis F. Cioffi 224 Fall 2016
d. You can write what would be a comment to the journal (and then if you like it,
3 (Mostly) Repeated from the earlier assignment
3.1 Important Constituents of Good Work
A. Good referencing. Because you must write your own words, the discussions on Slack
for this assignment will have to be more circumspect than usual. If you turn a good
phrase there or have a great insight and share it with everyone, that sharing makes
it impossible for everyone who reads it to claim it as their own. Please read carefully
this definition of plagiarism from the GWU Code of Academic Integrity on the student
Plagiarism ? intentionally or knowingly representing the words, ideas, or
sequence of ideas of another as one?s own in any academic exercise; or failure
to attribute any of the following: quotations, paraphrases, or borrowed
You may use the product of your classmates? (or anyone else?s) thinking to spur your
own, but you must give any individual credit by referencing the specific Slack link when,
as the quote above shows, paraphrasing or even just using ?borrowed information.?
If you find a particularly good phrase on Slack, you may use it but you must put it
inside quotation marks. And if you rewrite it to put it in your own words, you must
still reference it. Quoting words, directly or indirectly, and even ideas, from Slack or
elsewhere, is fine as long as that use is judicious, referenced, and does not constitute
a substantial component of your submission; the substance must come from you. All
submissions will be run through SafeAssign, so plagiarism will be found and will be
dealt with harshly.
B. Professionalism in Writing and Appearance.
(a) Unlike a blog, this formal paper requires formal English, and you will lose as much
as 25% of the grade for bad grammar, e.g., do not repeat the article author?s
mistake of following a compound subject (?Refutation and controversy?) with a
singular verb (?is?). You may certainly get assistance with your writing.
(b) Use a serif font with 11 or 12 point-size type. If you do not, expect another penalty
of up to 25% of the entire assignment.
(c) Line spacing should be either 1.5 or double spaced.
(d) The paper must have reasonable margins, and the numbers and letters that
correspond to the topics you are addressing. Err here, and another 25% is at risk.
(e) As we cleverly innovated last time, you may use the third page of this two-page
paper for your title (and references, if any) page, with your name and the date.
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Dr. Denis F. Cioffi 224 Fall 2016
Grading Rubric for the Eight Pointers
Points Grade Equivalent Criteria
0 or 1 Below C level Shows no understanding of the question and little
knowledge of the author?s arguments.
2 / 3 C / C+
Average arguments reflecting little beyond what
the article?s author himself has written; writing is
understandable, but explanations are mediocre.
4 / 5 / 6 B- / B / B+
More strong than weak or average arguments
buttressed by good understanding of examples.
Occasional good writing that shows room for
7 / 8 A / AGood
writing throughout. Communicates strong,
cogent arguments clearly and concisely, with no
grammatical errors and no unnecessary words; shows
insight and full understanding. Great flow from
beginning to end.
For the 25 pointers, multiply the point totals by 3.
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