@@ -54,7 +54,7 @@ These design probabilities in turn can be used to compute the conditional probab
5454
5555$$
5656\text{Pr}(A|r)=\frac{\pi_A \text{Pr}(r|A)}{\pi_A \text{Pr}(r|A)+ (1-\pi_A) \text{Pr}(r|A^{'})}
57- $$ (eq:one)
57+ $$ (eq:util-rand- one)
5858
5959
6060## Zoo of Concepts
7171\text{or}&\\
7272\text{Pr}(A^{'}|r)&>1-\pi_A
7373\end{aligned}
74- $$ (eq:two)
74+ $$ (eq:util-rand- two)
7575
7676From Bayes's rule:
7777
7878$$
7979\frac{\text{Pr}(A|r)}{\text{Pr}(A^{'}|r)}\times \frac{(1-\pi_A)}{\pi_A} = \frac{\text{Pr}(r|A)}{\text{Pr}(r|A^{'})}
80- $$ (eq:three)
80+ $$ (eq:util-rand- three)
8181
8282If this expression is greater (less) than unity, it follows that r is jeopardizing with respect to $A$($A^{'}$). Then, the natural measure of jeopardy will be:
8383
@@ -87,7 +87,7 @@ g(r|A)&=\frac{\text{Pr}(r|A)}{\text{Pr}(r|A^{'})}\\
8787&\text{and}\\
8888g(r|A^{'})&=\frac{\text{Pr}(r|A^{'})}{\text{Pr}(r|A)}
8989\end{aligned}
90- $$ (eq:four)
90+ $$ (eq:util-rand- four)
9191
9292
9393Suppose, without loss of generality, that $\text{Pr}(\text{yes}|A)>\text{Pr}(\text{yes}|A^{'})$, then a yes (no) answer is jeopardizing with respect $A$($A^{'}$), that is,
@@ -126,7 +126,7 @@ For that reason, Lanke (1976) {cite}`lanke1976degree` argued that ah appropriat
126126
127127$$
128128\max \left\{ \text{Pr}(A|\text{yes}) , \text{Pr}(A|\text{no}) \right\}
129- $$ (eq:five)
129+ $$ (eq:util-rand- five-a )
130130
131131Holding this measure constant, he explained under what conditions the smallest variance of the estimate was achieved with the unrelated question model or Warner's (1965) original model.
132132
@@ -138,7 +138,7 @@ They measured "private protection" as
138138
139139$$
140140\frac{1-\max \left\{ \text{Pr}(A|\text{yes}) , \text{Pr}(A|\text{no}) \right\} }{1-\pi_A}
141- $$ (eq:six)
141+ $$ (eq:util-rand- six)
142142
143143
144144### 2.4 Greenberg, Kuebler, Abernathy, and Horvitz (1977)
@@ -151,27 +151,27 @@ They defined the hazard for an individual in $A$ as the probability that he or s
151151
152152$$
153153\text{Pr}(\text{yes}|A)\times \text{Pr}(A|\text{yes})+\text{Pr}(\text{no}|A)\times \text{Pr}(A|\text{no})
154- $$ (eq:seven-a)
154+ $$ (eq:util-rand- seven-a)
155155
156156Similarly, the hazard for an individual who does not belong to $A$ would be
157157
158158$$
159159\text{Pr}(\text{yes}|A^{'})\times \text{Pr}(A|\text{yes})+\text{Pr}(\text{no}|A^{'}) \times \text{Pr}(A|\text{no})
160- $$ (eq:seven-b)
160+ $$ (eq:util-rand- seven-b)
161161
162162Greenberg et al. (1977) also considered an alternative related measure of hazard that "is likely to be closer to the actual concern felt by a respondent."
163163
164164The "limited hazard" for an individual in $A$ and $A^{'}$ is
165165
166166$$
167167\text{Pr}(\text{yes}|A)\times \text{Pr}(A|\text{yes})
168- $$ (eq:eight-a)
168+ $$ (eq:util-rand- eight-a)
169169
170170and
171171
172172$$
173173\text{Pr}(\text{yes}|A^{'})\times \text{Pr}(A|\text{yes})
174- $$ (eq:eight-b)
174+ $$ (eq:util-rand- eight-b)
175175
176176This measure is just the first term in $(7)$, i.e., the probability that an individual answers "yes" and is perceived to belong to A.
177177
@@ -210,28 +210,28 @@ Then there is an $r_i$ such that
210210
211211$$
212212\frac{\partial U_i\left(\text{Pr}(A|r_i),\phi_i\right) }{\partial \text{Pr}(A|r_i)} <0, \text{ for } \phi_i \in \left\{ \text{truth},\text{lie}\right\}
213- $$ (eq:nine-a)
213+ $$ (eq:util-rand- nine-a)
214214
215215and
216216
217217$$
218218U_i\left(\text{Pr}(A|r_i),\text{truth}\right)>U_i\left(\text{Pr}(A|r_i),\text{lie}\right) , \text{ for } \text{Pr}(A|r_i) \in [ 0,1]
219- $$ (eq:nine-b)
219+ $$ (eq:util-rand- nine-b)
220220
221221Suppose now that correct answer for individual $i$ is "yes".
222222
223223Individual $i$ would choose to answer truthfully if
224224
225225$$
226226U_i\left(\text{Pr}(A|\text{yes}),\text{truth}\right)\geq U_i\left(\text{Pr}(A|\text{no}),\text{lie}\right)
227- $$ (eq:ten-a)
227+ $$ (eq:util-rand- ten-a)
228228
229229
230230If the correct answer is "no," individual $i$ would volunteer the correct answer only if
231231
232232$$
233233U_i\left(\text{Pr}(A|\text{no}),\text{truth}\right)\geq U_i\left(\text{Pr}(A|\text{yes}),\text{lie}\right)
234- $$ (eq:ten-b)
234+ $$ (eq:util-rand- ten-b)
235235
236236Assume that
237237
@@ -249,15 +249,15 @@ At equality, constraint $(10.\text{a})$ determines conditional probabilities t
249249
250250$$
251251U_i\left(\text{Pr}(A|\text{yes}),\text{truth}\right)= U_i\left(\text{Pr}(A|\text{no}),\text{lie}\right)
252- $$ (eq:eleven)
252+ $$ (eq:util-rand- eleven)
253253
254254Equation $(11)$ defines a "truth border".
255255
256256Differentiating $(11)$ with respect to the conditional probabilities shows that the truth border has a positive slope in the space of conditional probabilities:
257257
258258$$
259259\frac{\partial \text{Pr}(A|\text{no})}{\partial \text{Pr}(A|\text{yes})}=\frac{\frac{\partial U_i\left(\text{Pr}(A|\text{yes}),\text{truth}\right) }{\partial \text{Pr}(A|\text{yes})}}{\frac{\partial U_i\left(\text{Pr}(A|\text{no}),\text{lie}\right) }{\partial \text{Pr}(A|\text{no})}}>0
260- $$ (eq:twelve)
260+ $$ (eq:util-rand- twelve)
261261
262262The source of the positive relationship is:
263263
350350V(\text{Pr}(A|\text{yes}) , \text{Pr}(A|\text{no}))
351351= &\frac{{\pi_A}^2 (1-\pi_A)^2}{n}\times \frac{1}{\text{Pr}(A|\text{yes})-\pi_A}\times \frac{1}{\pi_A-\text{Pr}(A|\text{no})}
352352\end{aligned}
353- $$ (eq:thirteen)
353+ $$ (eq:util-rand- thirteen)
354354
355355where the random sample with replacement consists of $n$ individuals.
356356
@@ -360,11 +360,11 @@ The following inequalities restrict the shapes of iso-variance curves:
360360
361361$$
362362\frac{d \text{ Pr}(A|\text{no})}{d\text{ Pr}(A|\text{yes})}\bigg|_ {\text{constant variance}}=\frac{\pi_A-\text{Pr}(A|\text{no})}{\text{Pr}(A|\text{yes})-\pi_A}>0
363- $$ (eq:fourteen-a)
363+ $$ (eq:util-rand- fourteen-a)
364364
365365$$
366366\frac{d^2 \text{ Pr}(A|\text{no})}{d\text{ Pr}(A|\text{yes})^2}\bigg|_ {\text{constant variance}}=- \frac{2 \left[ \pi_A-\text{Pr}(A|\text{no})\right] }{\left[ \text{Pr}(A|\text{yes})-\pi_A \right] ^2}<0
367- $$ (eq:fourteen-b)
367+ $$ (eq:util-rand- fourteen-b)
368368
369369From expression $(13)$ and $(14)$ we can see that:
370370
@@ -477,7 +477,7 @@ Lanke (1976) recommends a privacy protection criterion that minimizes:
477477
478478$$
479479\max \left\{ \text{Pr}(A|\text{yes}) , \text{Pr}(A|\text{no}) \right\}
480- $$ (eq:five)
480+ $$ (eq:util-rand- five-b )
481481
482482Following Lanke's suggestion, the statistician should find the highest possible $\text{ Pr}(A|\text{yes})$ consistent with truth telling while $\text{ Pr}(A|\text{no})$ is fixed at 0. The variance is then minimized at point $X$ in Figure 3.
483483
@@ -615,27 +615,27 @@ Greenberg et al. (1977) defined the hazard for an individual in $A$ as the proba
615615
616616$$
617617\text{Pr}(\text{yes}|A)\times \text{Pr}(A|\text{yes})+\text{Pr}(\text{no}|A)\times \text{Pr}(A|\text{no})
618- $$ (eq:seven-a )
618+ $$ (eq:util-rand- seven-aa )
619619
620620The hazard for an individual who does not belong to $A$ is
621621
622622$$
623623\text{Pr}(\text{yes}|A^{'})\times \text{Pr}(A|\text{yes})+\text{Pr}(\text{no}|A^{'}) \times \text{Pr}(A|\text{no})
624- $$ (eq:seven-a )
624+ $$ (eq:util-rand- seven-bb )
625625
626626They also considered an alternative related measure of hazard that they said "is likely to be closer to the actual concern felt by a respondent."
627627
628628Their "limited hazard" for an individual in $A$ and $A^{'}$ is
629629
630630$$
631631\text{Pr}(\text{yes}|A)\times \text{Pr}(A|\text{yes})
632- $$ (eq:eight-a )
632+ $$ (eq:util-rand- eight-aa )
633633
634634and
635635
636636$$
637637\text{Pr}(\text{yes}|A^{'})\times \text{Pr}(A|\text{yes})
638- $$ (eq:eight-b )
638+ $$ (eq:util-rand- eight-bb )
639639
640640According to Greenberg et al. (1977), a respondent commits himself or herself to answer truthfully on the basis of a probability in $(7)$ or $(8)$ **before** randomly selecting the question to be answered.
641641
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