23.12.2012 Views

Asking Sensitive Questions Using the Crosswise Model: Some ...

Asking Sensitive Questions Using the Crosswise Model: Some ...

Asking Sensitive Questions Using the Crosswise Model: Some ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The <strong>Crosswise</strong> <strong>Model</strong><br />

(Yu, Tian, and Tang 2007)<br />

Let<br />

◮ X be <strong>the</strong> observed answer (“A” or “B”)<br />

◮ Y be <strong>the</strong> sensitive question with πY = Pr(Y = yes)<br />

◮ Z be <strong>the</strong> non-sensitive question with πZ = Pr(Z = yes) �= 0.5<br />

◮ Cov(Y , Z) = 0<br />

Then: πA = Pr(X = A) = (1 − πY )(1 − πZ ) + πY πZ<br />

Hence: A natural estimator for πY is<br />

ˆπY = ˆπA + πZ − 1<br />

2πZ − 1<br />

Var(ˆπY ) = Var(ˆπA)<br />

(2πZ − 1) 2<br />

Note that formally <strong>the</strong> crosswise model is identical to Warner’s<br />

model.<br />

Jann/Jerke/Krumpal <strong>Sensitive</strong> <strong>Questions</strong> & <strong>the</strong> <strong>Crosswise</strong> <strong>Model</strong> Bremen 13.11.2009 17 / 23

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!