Temperature-based death time estimation in near equilibrium: Asymptotic confidence interval estimation

Area of Science:

• Forensic Science
• Biophysics
• Statistical Modeling

Background:

• Temperature-based death time estimation (TDE) is challenging when body core temperature nears ambient levels.
• The Marshall/Hoare and Henßge (MHH) method sets a lower core temperature bound (T_K) for reliable TDE, suggesting times >10h.
• A prior study introduced the variance-bias-tradeoff (VBT) method to extend TDE for near-equilibrium conditions.

Purpose of the Study:

• To further investigate the applicability of the variance-bias-tradeoff (VBT) method.
• To identify and define the upper temporal limit for VBT's validity in post-mortem interval estimation.
• To provide a method for calculating this upper limit in forensic casework.

Main Methods:

• Investigated the theoretical underpinnings of the VBT method.
• Analyzed the VBT method's performance across extended post-mortem intervals.
• Utilized frequentist confidence interval probability interpretation to explain limitations.

Main Results:

• Discovered that the VBT method has an unacknowledged upper limit in time since death.
• Developed an explicit formula to compute this upper limit for practical forensic use.
• Demonstrated why the VBT method's previously assumed universal validity below T_K was incomplete.

Conclusions:

• The VBT method, while valuable, is not universally applicable for all times since death in near-equilibrium scenarios.
• Calculating the VBT upper time limit is crucial for accurate forensic post-mortem interval estimation.
• This research refines TDE methods by addressing a critical limitation in near-ambient temperature conditions.