The Hospital Authority of Gwinnett County and the Cobb County/Kennestone Hospital Authority applied to the State Health Planning Agency for certificates of need to provide open heart surgery services. The planning agency denied the applications. Both Gwinnett and Kennestone appealed to the State Health Planning Review Board, which consolidated the appeals and allowed St. Joseph’s Hospital of Atlanta, Inc., and Piedmont Hospital, Inc., to intervene as existing open heart surgery service providers. The review board affirmed the planning agency’s denial of both applications. Gwinnett and Kennestone then appealed to the superior courts of their respective counties. The Gwinnett County Superior Court affirmed the review board’s denial of the Gwinnett application, while the Cobb County Superior Court reversed the review board’s denial of Kennestone’s application. The Hospital Authority of Gwinnett County appeals from the decision of the Gwinnett County Superior Court; St. Joseph’s and the planning agency appeal from the decision of the Cobb County Superior Court. Because these appeals raise the same issues, they are consolidated for our review.
1. The general assembly has created a statewide health planning system to be administered by the planning agency and the review board. OCGA § 31-6-1 et seq. The public policy and purpose of this system “are to ensure that adequate health care services and facilities are developed in an orderly and economical manner and are made available to all citizens and that only those health care services found to be in the public interest shall be provided in this state. To achieve this public policy and purpose, it is essential that appropriate health planning activities be undertaken and implemented and that a system of mandatory review of new institutional health services be provided. Health care services and facilities should be provided in a manner that avoids unnecessary duplication of services, that is cost effective, and that is compatible with the health care needs of the various areas and populations of the state.” OCGA § 31-6-1.
In carrying out this policy and purpose, health care facilities are required to apply for and receive certificates of need from the planning agency before they are allowed to offer certain services, including open heart surgery. OCGA §§ 31-6-2 (4), (5); 31-6-40. OCGA § 31-6-42 (a) provides that the planning agency’s grant or denial of certifi*408cates of need “shall be based on the applicable considerations specified in this Code section and reasonable rules promulgated by the planning agency interpretive thereof.” In the instant cases, the applicable considerations are found in OCGA § 31-6-42, State Health Planning Agency (SHPA) Rule 272-2-.08 and SHPA Rule 272-2-.09 (13). The considerations set forth in SHPA Rule 272-2-.08 are essentially the same as those set forth in OCGA § 31-6-42 and apply to all health care services for which a certificate of need is required. The considerations contained in SHPA Rule 272-2-.09 (13) apply only to adult open heart surgery services.
2. Kennestone and Gwinnett argue that the review board improperly emphasized the general considerations of SHPA Rule 272-2-.08 and OCGA § 31-6-42 over the specific considerations of SHPA Rule 272-2-.09. There is no way for this court to determine whether the review board placed more emphasis on either the specific or general consideration, since the board cites numerous considerations in its written decision and does not indicate that any single consideration is more important than another. Even if we assume that the review board interpreted the applicable statute and the planning agency’s own rules in such a way to place more emphasis on certain considerations, that interpretation is entitled to deference by this court. The interpretation of a statute by an administrative agency which has the duty of enforcing or administering it is to be given great weight and deference. North Ga. E.M.C. v. City of Calhoun, 195 Ga. App. 382, 384 (393 SE2d 510) (1990); City of LaGrange v. Ga. Power Co., 185 Ga. App. 60, 63 (363 SE2d 286) (1987).
Moreover, the position of Kennestone and Gwinnett that the specific criteria should prevail over the general considerations is premised on a rule of law that is inapplicable to the instant cases. Kennestone and Gwinnett rely upon the rule of statutory construction that a specific statute will prevail over a general statute, absent any indication of a contrary legislative intent, to resolve any inconsistency between them. City of LaGrange v. Troup County E.M.C., 200 Ga. App. 418, 423-424 (2) (408 SE2d 708) (1991); First Nat. Bank of Atlanta v. Sinkler, 170 Ga. App. 668, 670 (1) (317 SE2d 897) (1984). The reliance of Kennestone and Gwinnett on this rule is misplaced because, as both hospital authorities note in their briefs, the general and specific rules at issue in these cases are not inconsistent. Rather, the specific criteria set forth in SHPA Rule 272-2-.09 are intended by both the legislature and the planning agency to supplement and interpret the more general concepts found in SHPA Rule. 272-2-.08 and OCGA § 31-6-42. See SHPA Rule 272-2-.08 (2); North Fulton Community Hosp. v. State Health &c. Agency, 168 Ga. App. 801, 804 (2) (310 SE2d 764) (1983). Because the general and specific criteria applicable to the instant cases are not in conflict, the hospital authorities’ posi*409tion is without merit.
3. Kennestone and Gwinnett further claim that the review board not only emphasized the wrong criteria, but in fact failed to consider the specific criteria set forth in SHPA Rule 272-2-.09 (13). This claim is wholly without merit, as a review of the board’s written decision plainly shows that it cited and discussed the applicable specific criteria contained in SHPA Rule 272-2-.09 in addition to the general criteria. SHPA Rule 272-2-.09 (13) (b) (1) sets forth four conditions which must be met before a new adult open heart surgery service shall be approved. The review board did not refer to the first three conditions in its written decision, and therefore we presume for purposes of this appeal that Kennestone and Gwinnett met each of those three conditions. The board did, however, specifically address the fourth condition, which provides that “an applicant shall document that authorized adult open heart surgery services in the state are not predicted to be adversely impacted as a result of the establishment of the new service.” SHPA Rule 272-2-.09 (13) (b) (1) (iv). The rule then sets forth several methods for determining adverse impact. The method applicable to the instant cases provides that establishment of the new service will have an adverse impact if “an existing service which performed 350 or more procedures in the most recent year . . . would perform less than 350 procedures annually as a result of loss of open heart surgery referrals, unless the reduction in the existing service’s annual total volume would be ten percent or less.” SHPA Rule 272-2-.09 (13) (b) (1) (iv) (I). The review board expressly found that establishment of an open heart service at either Kennestone or Gwinnett would adversely impact the existing open heart service at Piedmont Hospital by reducing its procedures to fewer than 350 annually and by more than ten percent of its total annual volume. Since the face of the review board’s decision clearly shows that it was based on the applicable considerations set forth in SHPA Rule 272-2-.09, the claim of Kennestone and Gwinnett to the contrary is incorrect.
4. Kennestone and Gwinnett contend that the review board’s finding that establishment of an open heart surgery service at either hospital would adversely impact the existing service at Piedmont is not supported by sufficient evidence. A reviewing court may reverse this finding only if it is “[n]ot supported by substantial evidence, which shall mean that the record does not contain such relevant evidence as a reasonable mind might accept as adequate to support such findings, inferences, conclusions, or decisions, which such evidentiary standard shall be in excess of the ‘any evidence’ standard.” OCGA § 31-6-44 (i) (5). In the present cases, there is substantial evidence to support the board’s finding. An expert witness testified that establishment of the new service at Kennestone or Gwinnett would reduce the number of procedures performed annually at Piedmont to less than *410350 and by more than ten percent of its total annual volume. The expert explained the basis for this testimony and was thoroughly cross-examined about this opinion.
Kennestone and Gwinnett challenge the basis of the expert’s opinion. Those challenges, however, go only to weight and not the admissibility of the expert’s opinion. Krause v. Vance, 207 Ga. App. 615, 616 (1) (428 SE2d 595) (1993). A reviewing court may not substitute its judgment as to the weight of evidence on questions of fact. Bd. of Nat. Resources v. Walker County, 200 Ga. App. 301, 308 (5) (407 SE2d 436) (1991). The expert’s relevant testimony is such that a reasonable mind might accept it as adequate to support the review board’s finding that establishment of an open heart service at either Kennestone or Gwinnett would adversely impact the existing service at Piedmont. The review board did not err in denying certificates of need to both Kennestone and Gwinnett on this basis. The Gwinnett County Superior Court thus properly deferred to the review board’s decision denying the Gwinnett Hospital Authority’s application for a certificate of need. The Cobb County Superior Court, however, exceeded its role as a reviewing court and erred in reversing the board’s decision denying Kennestone’s application. The ruling of the Gwinnett County Superior Court is therefore affirmed and the ruling of the Cobb County Superior Court is reversed.
5. The parties’ remaining arguments are either moot or without merit.
Judgment affirmed in Case No. A93A1565, and judgment reversed in Case Nos. A93A1566 and A93A1567.
Pope, C. J., McMurray, P. J., Birdsong, P. J., Beasley, P. J., Cooper, Andrews and Smith, JJ., concur. Blackburn, J., dissents.