Dateline: July, 2010, Issue 1
The difference between direct and circumstantial evidence is difficult for jurors.
Tiersma and Curtis (2008) tested how well California's 2006 jury instruction (CACI No. 202) allowed jurors to identify direct and circumstantial evidence.
Even with this instruction, jurors struggled identifying direct and indirect evidence. Across 16 situations, only 62% of responses correctly identified whether the evidence offered to prove a fact was direct or circumstantial.
Jurors were better able to identify direct than circumstantial evidence. When the evidence offered to prove a fact was direct, 66% of responses correctly identified the evidence as direct. When the evidence offered to prove a fact was circumstantial, only 59% of responses correctly identified the evidence as indirect.
Jurors had the easiest time recognizing weak circumstantial evidence and strong direct evidence. By contrast, strong circumstantial evidence often was mistakenly classified as direct, and weak direct evidence often was mistakenly classified as circumstantial.
The researchers conclude that jurors are heavily influenced by the everyday meaning of circumstantial evidence as weak evidence.
Source Tiersma, P. & Curtis, M. (2008). Testing the comprehensibility of jury instructions: California's old and new instructions on circumstantial evidence. Journal of Court Innovation, 1, pp. 231-261.