W. Va. Code § 11-13R-3
(b) Terms defined. --
(1) "Base amount" means:
(10) "Research and development" means systematic scientific, engineering or technological study and investigation in a field of knowledge in the physical, computer or software sciences often involving the formulation of hypotheses and experimentation for the purpose of revealing new facts, theories or principles or increasing scientific knowledge which may reveal the basis for new or enhanced products, equipment or manufacturing processes.
(B) Research and development does not include:
(11) "Related person" means:
(D) A member of the same controlled group as the taxpayer.
For purposes of this article, "control", with respect to a corporation, means ownership, directly or indirectly, of stock possessing fifty percent or more of the total combined voting power of all classes of the stock of the corporation entitled to vote. "Control", with respect to a trust, means ownership, directly or indirectly, of fifty percent or more of the beneficial interest in the principal or income of the trust. The ownership of stock in a corporation, of a capital or profits interest in a partnership or association or of a beneficial interest in a trust is determined in accordance with the rules for constructive ownership of stock provided in section 267(c) of the United States Internal Revenue Code of 1986, as amended, other than paragraph (3) of that section. (12) "Taxpayer" means any person subject to the tax imposed by article twenty-three or twenty-four of this chapter or both. In the case of a sole proprietorship subject to neither the tax imposed by article twenty-three nor the tax imposed by article twenty-four, the term "taxpayer" means any sole proprietor who is subject to the tax imposed by article twenty-one of this chapter. (13) "This code" means the Code of West Virginia, 1931, as amended.