Robert M. Bloom (Boston College Law School) has posted What Jurors Should Know about Informants: The Need for Expert Testimony (Michigan State Law Review, Forthcoming) on SSRN. Here is the abstract:

With the advent of DNA exonerations, the data would indicate that many individuals have been wrongly convicted. In looking at the causes of the exonerations, nearly 20% have involved testimony by accomplices and jailhouse informants. The questionable credibility of these individuals has long been recognized by courts and legislatures. Reforms in this area include, enhanced jury instructions, pre-trial credibility hearings, and corroboration before the testimony can be introduced.

This article argues the efficacy of expert testimony to further assist jurors in measuring the credibility of these witnesses. Although the use of experts has largely been disfavored by courts, there has been a gradual movement to use experts for eyewitness identifications, the major cause of exonerations. The article proposes a similar movement for informant testimony.