When can a lay witness offer an opinion regarding the genuineness of a signature?

A lay witness can provide an opinion regarding the genuineness of a signature when they are familiar with that signature. This familiarity can arise from having observed the person's signature on prior occasions, allowing the witness to compare the signature in question with those they have previously seen. The law recognizes that personal experience can inform a lay person’s perception and judgment, enabling them to make a credible assessment of authenticity based on their observations.

The other options, while they might seem relevant in some contexts, do not satisfy the requirements for lay witness testimony as clearly as familiarity does. For instance, having studied the signature prior to trial may not confer the same level of personal familiarity as having observed it in a natural setting. Similarly, merely seeing the signature in the courtroom does not provide adequate context or exposure for an opinion to be formed. Lastly, having experience in handwriting analysis would typically require expert testimony, rather than lay witness testimony, as it involves specialized knowledge beyond what is expected from a layperson. Therefore, the key factor for a lay witness opining on the authenticity of a signature is their personal familiarity with it.