What is the test for determining whether a witness has sufficient experience in the field to be able to testify in a jury trial?

The court concluded the determinative issue in each case must be whether the witness has sufficient skill or experience in the field so that his testimony would be likely to assist the jury in the search for the truth, and "no hard and fast rule can be laid down which would be applicable in every circumstance." (11 Cal.3d at p. 645, 114 Cal.Rptr. 128, 522 P.2d 688.) Where a witness has disclosed sufficient knowledge, the question of the degree of knowledge goes more to the weight of the evidence than its admissibility. (Chadock v. Cohn (1979) 96 Cal.App.3d 205, 209, 157 Cal.Rptr. 640.)