Jury research is only a decade old and has been involved in a small percentage of cases, largely because it is expensive and the expertise is not widely available. Thus, most buyers of jury research have been law firms representing corporate giants and feisty small companies or individuals who feel they have a good case against a large company. The first major effort to use social science knowledge to affect a jury trial was on behalf of Berrigan and the other members of the Harrisburg Seven in 1971-72. After winning this case, the researchers involved offered their help to other political defendants and founded the National Jury Project in 1975. Lawyers customarily select jurors according to their own private judgments about their biases and use peremptory challenges to eliminate individuals who most worry them. Survey data can be used to show judges that so many persons in the jury pool are biased that a change of venue is necessary and help them ask jurors more sophisticated questions. Jury research also involves observing jurors' body language and pretesting different ways of presenting a case in front of mock juries.