Reanalysis of the Trotter Tibia Quandary and its Continued Effect on Stature Estimation of Past‐Conflict Service Members

Abstract

Forensic casework from past-conflicts relies on the corrected historical Trotter data for stature estimation in Fordisc. For roughly 10 years', stature estimation using this data has produced point estimates for the tibia that are on average 1.25 inches less than the other long bones. This issue was identified after applying the equations derived from Fordisc to the USS Oklahoma commingled assemblage. Reevaluation of Fordisc revealed that a correction factor of 20 mm, instead of 10 mm, was mistakenly applied to the Trotter tibia data. Historical forensic anthropology reports written at the Defense POW/MIA Accounting Agency were utilized to identify that the overcorrection is isolated to Fordisc 3 with an error rate of 5% of known antemortem statures falling outside of the prediction intervals that relied on the tibia. Further evaluation of the Oklahoma sample indicates the 10 mm correction is still producing point estimates less than the other long bones.

Measuring the Tibia: Trotter’s Error Revisited

“…That both ordinary length and "maximum length" were longer than WW2 core suggests that the former was measured as Trotter measured "maximum length", and "maximum length" was actually condylar-malleolar length, perhaps guided by Trotter's actual definition. This small series offers support for Lynch et al's (6) suggestion that some WW2 were measured to include the malleolus, but it has no bearing on stature estimation because there is no evidence it was ever used for that. During the course of this investigation, additional errors were discovered.…”

“…They found that the 10 mm adjustment in Jantz et al (2) produced height estimates systematically different when compared to other bones, and that an adjustment of 6 mm was more appropriate. Lynch et al (6) concluded this difference may be attributable either to a difference between how Trotter measured the Terry collection or to how the World War 2 (WW2) tibiae were measured. They suggest two possibilities.…”

“…Jantz et al (2) proposed adding 10 millimeters (mm) to Trotter’s measurement to make it comparable to condylar‐malleolar length, which is the definition given in Trotter and Gleser (1). Whether the 10 mm adjustment is appropriate has been called into question by Lynch et al (6) during the course of their investigation of the USS Oklahoma bone lengths. They found that the 10 mm adjustment in Jantz et al (2) produced height estimates systematically different when compared to other bones, and that an adjustment of 6 mm was more appropriate.…”

“…These data have been previously used to address various questions (8,9). The purpose of this paper is to address questions raised in Lynch et al (6) and to re‐evaluate the adjustment proposed in Jantz et al (2). Specifically, analyses will be designed to address questions as follows: Did Trotter measure Terry and WW2 the same way, as is clearly implied by her statement that she measured both series herself?…”

Generating a Vertebrae‐based Method to Discriminate between Korean and U.S. White Male Casualties from the Korean War,

“…A comparison of the current sample's Tib with those of Trotter and Gleser did not differ significantly (One sample t ‐test; p = 0.583 and p = 0.504 for the left and right Tib, respectively). This result was not affected by the 6 mm correction factor applied to the Trotter and Gleser's tibia length (One sample t ‐test; p = 0.176 and p = 0.204 for the left and right Tib, respectively). Therefore, it was concluded that no significant size discrepancies exist between the samples of this study and Korean War casualties.…”