This paper, the fourth and final in a series on the management of expert evidence during the Kilmore East bushfire proceeding, considers the use of assessors. During the proceeding, Justice J. Forrest appointed assessors to assist him with some of the most complex aspects of the expert evidence. The assessors played a significant role in the proceeding, helping to guide the expert conferences, sitting with Justice J. Forrest during the largest concurrent evidence session and participating in the examination of the experts. This paper is based on interviews conducted with some of the judges, barristers, solicitors and experts involved in the proceeding, and it records their reflections on whether the use of assessors was valuable. It appears that the use of assessors was a success, and all the participants interviewed regarded them as being beneficial to the trial. They were satisfied that the method of selection adopted by the Court was appropriate. The assistance the assessors provided Justice J. Forrest with understanding the expert evidence was essential, and having people capable of engaging in technical dialogue with the experts while they were giving evidence was useful. This paper suggests that the appointment assessors should be considered in future cases of similar complexity to help the trial judge deal with very difficult expert evidence.