Wednesday, March 5, 2008

Trouble by the Numbers

A rant from elsewhere, back in the Thesis Defense phase:

Multiple choice question. Graphs:

a) may or may not show all the work you put into creating them
b) present data much more coherently and completely than words and averages
c) are the product of THE DEVIL or his minions intent on creating chaos and frustration
d) all of the above

Let's consider these different options.

A) This is correct. Excel will automatically put standard error bars on any graphs, but as far as can be determined it pulls these numbers out of its electronic posterior. SPSS is supposed to have a button to add standard error bars, but this doesn't work. I spent two hours Tuesday manually entering standard error bars in Excel, and I will probably spend less than two minutes talking about each one.

B) Also correct. My powerpoint presentations contain few words, and dozens of images. Only one slide in my practice talk contained a verbal explanation of a finding rather than a visual one, and that was because I hadn't had time to create that graph yet. I promptly went and created a very pretty scatterplot showing the relationship between two measures in my experiment in hopes of impressing my committee that my research wasn't an entire null result. Looking at that pretty scatterplot, I discovered an undetected outlier, which let me remove it and make re-do the analyses before sending everything off to my committee.

C) Oh, is this ever correct. Thanks to that outlier, not only did I have to trudge through re-typing a lot of obscure numbers throughout my methods section, the entire meaning of the results for any analyses related to that measure changed, and I spent an entire evening re-writing chunks of my results and discussion section and reformulating my


D) All of the above. As in all such multiple choice questions, this is the correct answer. As thrilled as I am to discover that my experiment just became more meaningful in its "marginally significant" way, and that the error was discovered before sending a draft to my committee (they might read it, and changing conclusions for the defense probably wouldn't go over well), I spent most of a day fixing something that was supposed to have been finished. I fully intend to irrationally blame the graph for all that frustration. Ignorance is bliss; knowledge is a re-write.

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