Database Reference
In-Depth Information
CHAPTER
9
Can you relate?
Correlation and simple
linear regression
9.1
INTRODUCTION
Making sense of data, as we have noted, is a required skill for any UX researcher. No
matter what the data values are or how you got the data, you're the one who's respon-
sible for making sense of the data. Your other team members may casually watch you
conduct a usability test or two, but you are on the hook for interpreting the results.
Perhaps just as importantly, everyone (including top brass) wants to know what your
recommendations are based on your indings. Although rarely explicitly stated, you
know what those execs are thinking: “You told me what you observed; now tell me
what to do to increase my bottom line.”
Of course, we've already discussed lots of ways to analyze data to gain meaning
through statistical inference (hypothesis testing and conidence intervals) methods.
But, what about using data to determine the
relationship
between quantities, in order
to garner even more meaning? More speciically, how does the value of one variable
change when the value of another variable changes? Furthermore—and here comes
perhaps one of the most important concepts for not just UX, but all social and behav-
ioral researchers—how can we
predict
the value of one variable from the knowledge
of the value of another variable?
Enter the wonderful world of regression analysis.
9.2
CASE STUDY: DO RECRUITERS REALLY CARE ABOUT
BOOLEAN AT BEHEMOTH.COM?
Let's return to our favorite employment Web site, Behemoth.com, where you were
hired as usability researcher. As we mentioned in Chapter 3, Behemoth.com is aptly
named, because it's one of the largest job search engines in the world, with over a
million job openings at any time, over 1 million resumes in the database, and over
63 million job seekers per month. Behemoth has over 5000 employees spread around
the world.
You'll also recall from Chapter 3 that one of the main sources of Behemoth's
income is from employers and recruiters who (1) post jobs on the site and (2) buy
access to its enormous database of resumes to search for good candidates to ill those
jobs.
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