From the Classroom: The Opinion Evidence Rule and its Role in Criminal Investigations (Part I of II)

From the Classroom: The Opinion Evidence Rule and Criminal Investigations – Part I   
By Ray Hill    
Professor Emeritus, Santa Rosa Junior College   

This is the tenth in a series of bulletins covering the California Evidence Code and criminal investigations. The next two articles will cover the Opinion Evidence Rule as it relates to an officer, deputy or investigator giving testimony in court (140 E.C.).  

What is the Opinion Evidence Rule   

The Opinion Evidence Rule permits a lay witness (non-expert) to give an opinion during testimony when (800 E.C.):   

1) The testimony is rationally based upon the personal knowledge of the witness;   

2) The opinion is helpful to a clear understanding of one’s testimony; and   

3) The opinion relates to one or more of the areas qualifying for opinion testimony.    

The Opinion Evidence Rule has historical roots in Holland v. Zolmer (1894) 2 Cal. 633.  

Courts Favor Its Use in Testimony  

The law favors opinion evidence if the testimony will assist the trier of fact to reach a conclusion on a disputed fact.   

Examples:  

Courts have recognized that opinion testimony from a lay witness may be helpful when the matters observed by the witness were too complex or subtle to enable the witness accurately to convey them without ....

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