UPON REHEARING EN BANC
Opinion
BARROW, J.In this appeal, a rehearing en banc was granted from a decision of a panel in which there was a dissent.1 The appeal is from an award of the Workers’ Compensation Commission* and challenges the commission’s decision to include Crawley’s earnings from similar employment as a domestic worker in determining her average weekly wage. We hold that credible evidence supported the commission’s finding that Crawley was an employee, not an independent contractor, in her employment as a domestic worker. For this reason, we affirm the commission’s decision to include her earnings from similar employment.
While employed as a custodian for Metropolitan, Crawley received a compensable injury. Metropolitan paid her benefits based on an average weekly wage of $109.32 per week, the amount she was paid by Metropolitan.
Crawley worked for Metropolitan at National Airport on Saturdays and Sundays where she cleaned and supplied ladies’ rest rooms, swept and picked up trash in the public areas of the terminal, and dusted chairs and elevators. During the remainder of the week, she was a domestic, day worker in private homes where she “cleaned, dusted, swept, mopped and vacuumed in addition to cleaning windows and washing cabinets.” In one home, she also assisted an infirm lady in taking baths.
Crawley applied to the commission to include her earnings as a day worker in calculating her average weekly wage. Metropolitan contended that her other earnings should not be included because they were derived from work she did as an independent contractor, not as an employee. The commission found that Crawley was “employed as a day worker or a ‘servant’ rather than as an inde*264pendent contractor” and concluded, therefore, that her earnings from other, similar employment should be included in determining her average weekly wage.
“[A]verage weekly wages” include “the earnings of the injured employee in the employment in which he was working at the time of the injury.” Code § 65.1-6.2 For this purpose, “earnings” include not only earnings from the employer for whom the employee was working at the time of the accident but also earnings from similar services from other employment. First Virginia Banks, Inc. v. McNeil, 8 Va. App. 342, 344, 381 S.E.2d 357, 358 (1989). Earnings from other similar employment may include domestic employment even though domestic employees are excluded from coverage under the act. Id.
“[T]he earnings of the injured employee” for this purpose are not expressly limited to wages earned by an employee, see Code § 65.1-6, and Crawley contends that whether she is an employee in her other employment is immaterial so long as her earnings from such employment resulted from performing similar services as those required by her covered employment. We need not address this issue because we conclude that the commission’s finding that Crawley was an employee is supported by credible evidence.
“What constitutes an employee is a question of law”; however, whether a specific person falls within that definition “is usually a question of fact.” Intermodal Servs., Inc. v. Smith, 234 Va. 596, 600, 364 S.E.2d 221, 223 (1988) (quoting Baker v. Nussman, 152 Va. 293, 298, 147 S.E. 246, 247 (1929)). Generally, “a person is an employee if he works for wages or a salary and the person who hires him reserves the power to fire him and the power to exercise control over the work to be performed.” Richmond Newspapers v. Gill, 224 Va. 92, 98, 294 S.E.2d 840, 843 (1982). “The right of control is the determining factor in ascertaining” whether one is an employee or not. Smith, 234 Va. at 601, 364 S.E.2d at 224. This right of control includes “the power *265to specify the result to be attained [and] the power to control ‘the means and methods by which the result is to be accomplished.’ ” Id. A person is an employee if the person for whom he or she is working “has the power to direct the means and methods by which [he or she] does the work.” Id.
The parties stipulated that Crawley was a sole proprietor while performing her domestic, day work. A sole proprietor, however, is not necessarily an independent contractor. A sole proprietor may have employees who are subject to the provisions of the act. See Smith v. Weber, 3 Va. App. 379, 381, 350 S.E.2d 213, 214 (1986). A sole proprietor may also elect to be an employee covered by the act. Code § 65.1-4.2. Whether a sole proprietor who does not so elect is an employee or an independent contractor depends upon the nature of the relationship, particularly whether the person who hires him or her retains the right to control the work to be performed. See Smith, 234 Va. at 601, 364 S.E.2d at 224. Whether such a person is an employee under the act is usually a question of fact. Id. at 600, 364 S.E.2d at 224. The stipulation that Crawley was a sole proprietor is not, therefore, conclusive in determining whether she is an employee or an independent contractor in her similar employment.
As a sole proprietor, Crawley paid her own federal, state and social security taxes on the income she received from her domestic, day work. This fact, although persuasive, is also not conclusive in resolving whether she was an employee “under the control of [her] employer.”
Crawley either reported to or was transported to each of the homes where she worked. She was not required to furnish her own tools or supplies. Furthermore, the commission found that “the nature of the employment in which [she] engaged ... is the kind of work over which each employer had direct control.”
An administrative agency is expected to “apply expert discretion to the matters coming within its cognizance.” Virginia ABC Comm’n v. York St. Inn, Inc., 220 Va. 310, 315, 257 S.E.2d 851, 855 (1979) (quoting Schmidt v. Board of Adjustment, 9 N.J. 405, 423, 88 A.2d 607, 615-16 (1952)). Accordingly, we must “give deference to the expertise and knowledge of the agency in the area which it supervises and regulates.” Johnson v. Virginia Employment Comm’n, 8 Va. App. 441, 448, 382 S.E.2d 476, 479 *266(1989).
As a fact finder, a commission established by the legislature to decide workers’ compensation disputes “acquires an expertise and accumulates an experience in [its] limited, specialized field often more extensive than that of the judiciary.” Dunton v. Eastern Fine Paper Co., 423 A.2d 512, 514 (Me. 1980) (quoting Jacobsky v. D’Alfonso & Sons, Inc., 358 A.2d 511, 514 (Me. 1976)). The scope of a judicial review of the fact finding function of a workers’ compensation commission is “severely limited, partly in deference to the agency’s expertise in a specialized field.” Brown v. Workmen’s Compensation Appeal Bd. (Transworld Airlines), 505 Pa. 35, 38, 476 A.2d 900, 902 (1984); see also Szumski v. Dale Boat Yards, Inc., 48 N.J. 401, 410, 226 A.2d 11, 16, cert. denied, 387 U.S. 944 (1967); Tallman v. ABF (Arkansas Best Freight), 108 N.M. 124, 130, 767 P.2d 363, 369 (Ct. App.), cert. denied, 107 N.M. 785, 781 P.2d 305 (1988). Such deference to an administrative agency’s fact finding because of its “technical expertise [and] more extensive experience [is appropriate] so long as its decision is reasonable and rational.” Wright’s Furniture Mill, Inc. v. Industrial Comm’n of Utah, 707 P.2d 113, 114 (Utah 1985).
The commission’s finding that Crawley performed “the kind of work over which each employer had direct control [is a finding within the commission’s] expertise and knowledge ... in the area which it supervises and regulates.” Johnson, 8 Va. App. at 448, 382 S.E.2d at 479. This finding was based on the commission’s examination of the nature of Crawley’s work as a domestic, day worker. The commission’s finding was a reasonable and rational inference based on the evidence presented. We, therefore, defer to the commission regarding this finding.
An award of the commission is “conclusive and binding as to all questions of fact.” Code § 65.1-98. Although the evidence was conflicting, credible evidence supported the commission’s finding that Crawley was an employee. We cannot disturb this finding. Therefore, the commission’s decision is affirmed.
Affirmed.
Benton, J., Coleman, J., Elder, J., Moon, J., and Willis, J., concurred.
The decision of the panel is reported at 12 Va. App. 1167, 408 S.E.2d 570 (1991).
Formerly the Industrial Commission of Virginia. Effective October 1, 1991, Title 65.1 was recodified as Title 65.2. All references in this opinion are to Title 65.1, in effect at the time the Commission’s decision was rendered in this case.
Code § 65.1-6 reads in part:
Unless the context otherwise requires, “average weekly wages” means the earnings of the injured employee in the employment in which he was working at the time of the injury during the period of fifty-two weeks immediately preceding the date of the injury, divided by fifty-two.