In Tieberg v. Unemployment Ins. App. Bd. (1970) 2 Cal.3d 943, the director of employment (director) levied assessments against a television production company for unemployment insurance contributions assertedly due based on salaries paid to writers who were employed to write television stories and plays. Such contributions were required only if the writers were employees rather than independent contractors. (Id. at p. 946.) The trial court agreed with the director and found that the writers were employees; the production company appealed. (Ibid.) The Supreme Court held that in determining that the production company was an employer, the trial court "improperly restricted its consideration to whether the production company had the right to and did exercise control over the writers' work." (Ibid.) It explained that while the right of control is the "principal test" of an employment relationship, the court should also have considered the additional factors identified in Empire Star Mines Co. v. Cal. Emp. Com. (1946) (Id. at pp. 946-947.) Indeed, it said, while the right to control and direct the individual who performs services as to the details and means by which the result is accomplished is the most important consideration, it is "not the only element in determining whether an employment relationship has been created." (Id. at p. 950.) The court thus considered all of the Empire Star factors before agreeing with the trial court that an employment relationship existed between the production company and its writers. (Id. at p. 955.)