Hi Mike:
What I mean by "what question you are trying to answer" is that if you are
interested in a specific fitting parameter, you might wish to make some
assumptions and put constraints on other parameters so that you can
extract the trend that you are interested in.
Carlo
On Tue, 13 Aug 2019, Mike Massey wrote:
It is true that we both have background information regarding the samples, and
similar goals in terms of the questions we are looking to answer.
"You also need to think about what question you are trying to answer. If you have a
specific goal in mind, then you may choose a different model than the individual who is
seeking the answer to a different question."
This is, somewhat, the issue we are grappling with. A reasonable EXAFS fit is one
interpretation of the data, but we are trying to find a way to deal with the problem of
seeing what one wants to see in EXAFS data. To me, it's a bit of a problem, anyway. A
version of "confirmation bias," I suppose.
The hope is that, if two of us independently reach a similar conclusion, we can
have more confidence in the findings, perhaps?
On Aug 13, 2019, at 7:59 PM, Carlo Segre <se...@iit.edu> wrote:
The answer you get will depend somewhat on the assumptions you make. if you
are truly provided with data and no other information about the sample, then
the job is challenging. If you know something about the sample that can help
you start in a particular direction then the two analyses have a better chance
of converging but it still depends on how you decide to approach the structural
model.
You also need to think about what question you are trying to answer. If you
have a specific goal in mind, then you may choose a different model than the
individual who is seeking the answer to a different question.
The most likely way to approach this problem is to both have the same
background information about the sample(s) and to mutually determine what
question you are trying to answer.
Cheers,
Carlo
On Tue, 13 Aug 2019, Mike Massey wrote:
I'm the dumb one. But it's an interesting question, and gets perhaps to the
heart of the issue: to what extent does the smartness of the analyst, or their
experience, or the fitting procedures used, or a butterfly flapping its wings
in Micronesia, impact the results?
For the sake of argument, can two equally smart and experienced analysts
working on fitting the same EXAFS spectra be expected to reach similar
conclusions? I guess we'll find out.
Another colleague once said something like, "EXAFS is great: you publish a paper,
then later you publish another paper re-analyzing the same data." Of course, he's a
strictly computational guy, so I'm not sure he necessarily has standing to
criticize...(Good-natured sarcasm font...)
On Aug 13, 2019, at 6:43 PM, Anatoly Frenkel <anatoly.fren...@stonybrook.edu>
wrote:
Are they equally smart?
Anatoly
On Aug 13, 2019, at 9:39 PM, Mike Massey <mmas...@gmail.com> wrote:
Hi Everyone,
I'm curious, has anyone ever tried turning two analysts loose on the same
unknown EXAFS spectrum to see if their fits come out with similar conclusions?
If you have tried it, how did it work out? Were the conclusions indeed similar?
If not, why not, and what did you end up doing about it?
I was talking with a colleague today about our plans for data analysis, and we
settled on this approach (since there are two interested parties willing to try
to fit a series of unknown EXAFS datasets).
The hope is, of course, that the two analysts will independently reach similar
conclusions with similar fits and structural models, but to my mind that
outcome is by no means guaranteed. Given the (presumably) wide variation in
fitting customs and procedures, I can envision a scenario in which there are
major differences.
This got me wondering, "Has anyone tried this?" So I thought I'd ask.
Your thoughts and experiences would be welcome. Thanks!
Mike Massey
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--
Carlo U. Segre -- Duchossois Leadership Professor of Physics
Directory, Center for Synchrotron Radiation Research and Instrumentation
Illinois Institute of Technology
Voice: 312.567.3498 Fax: 312.567.3494
se...@iit.edu http://phys.iit.edu/~segre se...@debian.org
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--
Carlo U. Segre -- Duchossois Leadership Professor of Physics
Directory, Center for Synchrotron Radiation Research and Instrumentation
Illinois Institute of Technology
Voice: 312.567.3498 Fax: 312.567.3494
se...@iit.edu http://phys.iit.edu/~segre se...@debian.org
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