Expert Testimony and CSLI (Rule 702 and cell site location information)

In this recent S.C. Court of Appeals case, Judge Hill gives a deep and thorough refresher on expert evidence and how a trial judge should evaluate if they have complied with SCRE 702.

The expert in this case testified about cell site location information (CSLI)...which in short is the information about where a cell phone might have been located on a certain date based on how it pinged from tower to tower (Judge Hill did a great job explaining in depth how this technology works as well in the opinion).

Judge Hill lays out the step by step process for evaluating this testimony with SCRE 702.

1. First, the trial judge must determine that the testimony is outside of the ordinary knowledge of the jury.

2. Then the judge weighs probative and prejudicial effects under SCRE 403.

3. Then the trial judge determines if the evidence is scientific or non-scientific in nature and applies the standards. For a blog post on the difference, click here.

In this case, the court held that CSLI is more technical than scientific and proceeded to analyze under the non-scientific standard. The court upheld the trial court in admitting the expert testimony.