He made use of official documents, arrest reports, trial transcripts and the like, but also made heavy use of informants who were participants in the illegal activities he was researching. Once again, much of what he found contradicted the officially held view of organized crime. Similarly, William Chambliss and John Gardiner have produced classic works on organized crime using official documents and personal interviews and observations. Chambliss engaged in interviews, participant observation, the use of informants, and the collection of official documents and newspaper stories to support his study. Researching organized crime has always presented immense difficulties for social scientists.
Traditional methods abound with problems of reliability and validity.
Data from both the state and the media have been unreliable and often distorted. Field research techniques have been effective in exploring local criminal organizations, but their applicability to organizations operating across international frontiers is questionable. So, we are faced with the problem of developing new departures and innovative techniques to explore the future. But the starting point in more or less the same as in the past, an exploration of the organizational aspects of organized crime. Research on the network itself.