2023 Wisconsin Statutes & Annotations › Chapter 909 - Evidence — authentication and identification. › 909.01 - General provision.

909.01
General provision.
The requirements of authentication or identification as a condition precedent to admissibility are satisfied by evidence sufficient to support a finding that the matter in question is what its proponent claims.
History:  Sup. Ct. Order, 59 Wis. 2d R1, R329 (1973); 1975 c. 41.
Unauthenticated ledger and signature cards bearing the entry “P.O.D. to (plaintiff)" were not competent evidence of the decedent's intent to make a savings and loan account payable on death to the plaintiff. Bruckner v. Prairie Federal Savings & Loan Ass'n, 81 Wis. 2d 215, 260 N.W.2d 256 (1977).
Before a demonstrative videotape may be admitted, there must be a foundation that it is a fair and accurate reproduction of what was seen and that it was produced under conditions reasonably similar to conditions of the actual event. Even with the foundation established, the evidence may be excluded on a finding that its probative value is outweighed by its prejudicial effect. State v. Peterson, 222 Wis. 2d 449, 588 N.W.2d 84 (Ct. App. 1998), 97-3737.
Computer-generated animation used as a demonstrative exhibit to show the scene and events of an alleged crime is not exempt from longstanding foundation requirements. Demonstrative computer-generated animation should be introduced in conjunction with the witness's testimony it seeks to clarify, as any diagram or photo intended to clarify a lay witness's testimony would be introduced. In this case, the animation was testified to by the animator and not by any witness and was nothing more than bits and pieces from each of the state's witnesses that, when mixed together, effectively represented the animator's own version of what occurred at the time and place in question. State v. Denton, 2009 WI App 78, 319 Wis. 2d 718, 768 N.W.2d 250, 07-2825.
A court should not afford a presumption of accuracy to a particular electronic monitoring device (EMD) report or EMD until the state has put forth evidence regarding the installation of the specific device and testimony as to its accuracy and reliability by a Department of Corrections employee familiar with its operation. Consequently, the state is permitted to authenticate and lay a foundation for an EMD report by providing testimony describing the electronic monitoring system and the process by which the daily summary reports are generated and showing that this process produces an accurate result. State v. Kandutsch, 2011 WI 78, 336 Wis. 2d 478, 799 N.W.2d 865, 09-1351.
Authentication does not require proving that the documents are incontrovertibly what they purport to be, but rather authentication requires presenting evidence sufficient to support a finding that the documents are what they purport to be. Horak v. Building Services Industrial Sales Co., 2012 WI App 54, 341 Wis. 2d 403, 815 N.W.2d 400, 11-0414.
Authentication can be done through circumstantial evidence. State v. Giacomantonio, 2016 WI App 62, 371 Wis. 2d 452, 885 N.W.2d 394, 15-0968.
Text message authentication is a low standard that can be achieved with the sort of testimonial evidence of a witness with knowledge and circumstantial evidence that was presented in this case. Text and other electronic messages do not require new rules on authentication. State v. Giacomantonio, 2016 WI App 62, 371 Wis. 2d 452, 885 N.W.2d 394, 15-0968.
In this case, the state's authentication obligation was to present sufficient evidence to support a finding that the records produced by the state were in fact Fitbit's records associated with a particular Fitbit device. The circuit court's obligation was not to scrutinize every line of data within the given record and decide whether each line was an accurate representation of the facts. Rather, once the circuit court concluded the factfinder could find that the records were what their proponent claimed them to be, the credibility and weight ascribed to those records were questions left to the finder of fact. State v. Burch, 2021 WI 68, 398 Wis. 2d 1, 961 N.W.2d 314, 19-1404.
Virtual DNA: Whole Device Authentication. O'Shea. Wis. Law. July/Aug. 2019.