MCG was approached by a Kentucky investigator with a fascinating proposal: to determine what is the probability that a miniature in their possession portrayed a 33-year old Abraham Lincoln. This concept was especially interest given the fact that, if the individual portrayed in the miniature is actually Lincoln, this would become his earliest known portrait.
The story behind this miniature was equally fascinating, as it was discovered by a couple who purchased a home which, as was later determined, had been owned by a direct relative of Abraham Lincoln. At the time in which MCG became involved in this project, the owner of this artifact had conducted forensic and historical analyses which suggested that it might indeed be portraying Abraham Lincoln… but the analysis was not backed by any quantitative analysis.
MCG conducted the analysis in two ways. First, the probability that the prior owner of the home where the miniature was found was actually a relative of Abraham Lincoln was determined. This analysis was based on the number of degrees of separation between that individual and Lincoln, and on the reliability of the historical records documenting each of the familiar relationships. Following that, MCG conducted an analysis grounded on Bayesian statistics, in which the probability that the miniature portrayed Lincoln given the information at hand (resemblance between Lincoln and the individual in the portrait, place in which the miniature was found, age of the miniature, etc.) was estimated.
Combining both approaches, MCG was able to estimate the mathematical probability that the individual in the portrait was actually Abraham Lincoln. No “black box” calculations were conducted – each step of the estimation was clearly explained in the report and can be replicated by independent investigators interested in examining this issue.
