What technique is impermissible for a lay witness when giving an opinion on a signature?

A lay witness is permitted to express opinions based on their personal knowledge and experience, but there are limitations, especially regarding technical matters such as handwriting analysis. In the context of a lay witness giving an opinion about a signature, comparing the disputed signature in court is deemed impermissible because it requires a level of forensic analysis and specialized knowledge that a layperson typically does not possess. Lay witnesses must rely on their perceptions and experiences rather than engage in a direct comparison, which implies a level of expertise and a methodical approach that is reserved for expert witnesses.

In contrast, providing the history of the signer's handwriting involves sharing observations that the lay witness has directly experienced, which is permissible. Referencing expert analyses might be more complex, but it could be part of the context if the lay witness speaks about what others have determined, as long as they are not providing their own expert interpretation. Identifying the signature's location is merely a fact-based observation and does not require an opinion or expertise, thus is allowable for a lay witness.