In S. G. Borello & Sons, Inc. v. Department of Industrial Relations (1989) 48 Cal.3d 341, considered whether agricultural workers were employees or independent contractors within the meaning of the Workers' Compensation Act. It discussed the relevant legal principles as follows: "Following common law tradition, California decisions ... uniformly declare that 'the principal test of an employment relationship is whether the person to whom service is rendered has the right to control the manner and means of accomplishing the result desired. ...' However, the courts have long recognized that the 'control' test, applied rigidly and in isolation, is often of little use in evaluating the infinite variety of service arrangements. While conceding that the right to control work details is the 'most important' or 'most significant' consideration, the authorities also endorse several 'secondary' indicia of the nature of a service relationship." (48 Cal.3d at p. 350.) Those "secondary indicia" "have been derived principally from the Restatement Second of Agency." (Id. at p. 351.) They generally " 'cannot be applied mechanically as separate tests; they are intertwined and their weight depends often on particular combinations.' " (Ibid.) After reviewing the factors traditionally considered to determine whether workers are employees or independent contractors, the court declined to adopt new standards for examination of the issue. Instead, it determined that "the Restatement guidelines heretofore approved in our state remain a useful reference." (Borello, supra, 48 Cal.3d at p. 354.) It also noted with approval "the six-factor test developed by other jurisdictions ... . Besides the 'right to control the work,' the factors include (1) the alleged employee's opportunity for profit or loss depending on his managerial skill; (2) the alleged employee's investment in equipment or materials required for his task, or his employment of helpers; (3) whether the service rendered requires a special skill; (4) the degree of permanence of the working relationship; and (5) whether the service rendered is an integral part of the alleged employer's business. " (Id. at pp. 354-355.) It concluded: "As can be seen, there are many points of individual similarity between these guidelines and our own traditional Restatement tests. We find that all are logically pertinent to the inherently difficult determination whether a provider of service is an employee or an excluded independent contractor ... ." (Id. at p. 355.)