Jury questionnaires are typically designed by the lawyers involved in the case, as described by the Attorney Education Center website. Most jury questionnaires ask for simple demographic information, but they can get quite involved, according to The New York Times.
Jury questionnaires are used by trial lawyers to find good candidates for their case's jury, states the Attorney Education Center. They can be used to discover the true opinions of jurors without the social pressure that comes from "show-of-hands" questions directed at groups. The New York Times describes jury questionnaires as sometimes containing very obscure or open-ended questions in order to discover any possible bias in a juror. It also state that lawyers sometimes use jury consultants to help them design questions. Jury questionnaires are more likely to be allowed by the presiding judge when both defense and prosecution collaborate in designing the questions.