What is the test for determining whether a breach of fiduciary duty was a legal cause of damage to appellant?

The only remaining question is whether there was sufficient evidence, either disputed or undisputed, that the alleged breaches of fiduciary duty or professional negligence were legal causes of damage to appellant. (See Lysick v. Walcom (1968) 258 Cal.App.2d 136, 153, 65 Cal.Rptr. 406.) It is plaintiff's burden to establish " 'a reasonable basis for the conclusion that it was more likely than not that the conduct of the defendant was a substantial factor in the result.' " (Ibid.) We conclude that appellant's evidence is sufficient to raise questions of fact under this standard of causation.