Although the State lost the appeal in Hernandez v. State, the opinion contains lots of hints on how to win next time without a lengthy hearing of live testimony from an expert witness.

First, the opinion suggests that live testimony is not required to meet the state's burden of showing by clear and convincing evidence that a scientific principle and the applicable techniques are reliable. Affidavits, copies of scientific articles, reports, etc., are "just swell" for proving up the reliability. This is consistent with Rule of Evidence 101(d)(1)(A), which indicates that the Rules don't apply to a decision by the judge regarding the admissibility of evidence.

Second, it is clear that the State can rely on a published opinion to show that another court has already found the principle reliable.

Perhaps TDCAA should begin developing a database for proving up certain standard scientific principles (e.g., instruments used to identify presence of a controlled substance). Then, when a prosecutor is caught in trial and needs to put a drug result into evidence, the prosecutor can download the supporting information from TDCAA's web site and offer it into evidence without the expense of bringing in the guy who built the instrument.

In addition, the web site can keep an updated list of cases holding that a particular scientific principle is valid (e.g., Emerson v. State for HGN). I will also begin keeping a list for the next update of The Predicate Manual.

Rob, what do you think?