A Survey Design for a Sensitive Binary Variable Correlated with Another Nonsensitive Binary Variable

Table 1

The main questionnaire for the combination questionnaire model.

Category	𝑊=1	𝑊=2	𝑊=3
I: {𝑋=0,𝑌=0}	Block 1: —	Block 2: —	Block 3: —
II: {𝑋=1,𝑌=0}	Category II: Please put a tick in Block 2
III: {𝑋=1,𝑌=1}	Category III: Please put a tick in Block 3
IV: {𝑋=0,𝑌=1}	Block 4: —

Note: Only {𝑋=1} is a sensitive class, while {𝑋=0}, {𝑌=0}, and {𝑌=1} are nonsensitive classes.