
577 N.W.2d 200 (1998)
PALO GROUP FOSTER CARE, INC., Petitioner-Appellant,
v.
MICHIGAN DEPARTMENT OF SOCIAL SERVICES, Respondent-Appellee.
Docket No. 195227.
Court of Appeals of Michigan.
Submitted February 4, 1998, at Grand Rapids.
Decided February 20, 1998, at 9:00 a.m.
Released for Publication May 5, 1998.
*201 Hess & Hess P.C. by John H. Hess, Grand Rapids, for Petitioner-Appellant.
Frank J. Kelley, Attorney General, Thomas L. Casey, Solicitor General, H. Daniel Beaton, Jr., Assistant Attorney General, for Respondent-Appellee.
Before HOOD, P.J., and MacKENZIE and MURPHY, JJ.
PER CURIAM.
Petitioner, Palo Group Foster Care, Inc., appeals, by leave granted, an order of the circuit court. That order affirmed an administrative agency decision by respondent, Michigan Department of Social Services, that denied renewal of petitioner's adult foster care facility license. We affirm.
In 1981, petitioner was licensed to operate a twenty-bed adult foster care home in Kent County, Michigan. Petitioner received regular, two-year renewals of its license in 1983, 1985, 1987, 1989, and 1991. In April 1993, however, petitioner was advised that its license would not be renewed. In May, an informal conference was held pursuant to respondent's internal policy manual, known as memorandum DOP 84-05. On June 18, 1993, the director of respondent's Bureau of Regulatory Services mailed to the petitioner a notice of the decision to refuse to renew petitioner's license.
Respondent refused to renew petitioner's license pursuant to § 22(1) of the Adult Foster Care Facility Licensing Act, M.C.L. § 400.722(1); M.S.A. § 16.610(72)(1). That section provides that the respondent may refuse to renew a license if the licensee has *202 wilfully and substantially violated the act or the rules promulgated under the act. In refusing to renew petitioner's license, respondent relied on three license violation complaint investigation reports, which alleged various violations of respondent's rules between December 1992 and February 1993. The complaints alleged, among other things, financial exploitation of a resident, failure to provide medication, and failure to provide dry clothing for a resident who was incontinent. Respondent also relied on several previous violations dating back to the mid-1980s. After a hearing, a hearing referee concluded that respondent had established the majority of the "willful and substantial" alleged violations.
Respondent's decision was stayed pending administrative appeal and subsequent appeal to the circuit court. The circuit court ultimately dissolved the stay upon affirming the administrative agency decision. This Court granted leave to appeal, but denied petitioner's request for a stay. Consequently, petitioner's foster care facility has been closed since May 31, 1996.

I
Petitioner first argues that because the appeal to the circuit court was based on § 25 of the Adult Foster Care Facility Licensing Act, M.C.L. § 400.725; M.S.A. § 16.610(75), the circuit court was obliged to engage in review de novo on appeal. Section 25 provides, in relevant part:
A person aggrieved by the decision of the director following a hearing under section M.C.L. § 400.722; M.S.A. § 16.610(72) or M.C.L. § 400.723; M.S.A. § 16.610(73), within 10 days after receipt of decision, may appeal to the circuit court for the county in which the person resides by filing with the clerk of the court an affidavit setting forth the substance of the proceedings before the department and the errors of law upon which the person relies, and serving the director with a copy of the affidavit. The circuit court shall have jurisdiction to hear and determine the questions of fact or law involved in the appeal. [Emphasis added.]
In response, respondent maintains that judicial review of the administrative agency's findings of fact is limited to the "competent, material and substantial evidence" standard set forth in the Michigan Administrative Procedures Act (APA), M.C.L. § 24.201 et seq.; M.S.A. § 3.560(101) et seq., and Const. 1963, art. 6, § 28.
Const. 1963, art. 6, § 28 provides, in relevant part:
All final decisions, findings, rulings and orders of any administrative officer or agency existing under the constitution or by law, which are judicial or quasi-judicial and affect private rights or licenses, shall be subject to direct review by the courts as provided by law. This review shall include, as a minimum, the determination whether such final decisions, findings, rulings and orders are authorized by law; and, in cases in which a hearing is required, whether the same are supported by competent, material and substantial evidence on the whole record. [Emphasis added.]
The scope of review provided by § 106 of the APA provides, in relevant part:
(1) Except when a statute or the constitution provides for a different scope of review, the court shall hold unlawful and set aside a decision or order of an agency if substantial rights of the petitioner have been prejudiced because the decision or order is any of the following:
* * * * * *
(d) Not supported by competent, material and substantial evidence on the whole record. [M.C.L. § 24.306; M.S.A. § 3.560(206). Emphasis added.]
No Michigan court has previously decided the question of the appropriate standard for a circuit court's review under M.C.L. § 400.725; M.S.A. § 16.610(75). The appropriate standard of review is a question of law, which we review de novo on appeal. Rapistan Corp. v. Michaels, 203 Mich.App. 301, 306, 511 N.W.2d 918 (1994). A litigant seeking judicial review of a decision by an administrative agency has three potential avenues of relief: (1) the review prescribed in the statute applicable to the particular agency; *203 (2) an appeal pursuant to the Revised Judicature Act, M.C.L. § 600.631; M.S.A. § 27A.631, and Const. 1963, art. 6, § 28; or (3) the method of review provided by the APA. Living Alternatives for the Developmentally Disabled, Inc. v. Dep't of Mental Health, 207 Mich.App. 482, 484, 525 N.W.2d 466 (1994).
Respondent is correct that under the APA the specified standard for judicial review is not de novo. Michigan Waste Systems v. Dep't of Natural Resources, 147 Mich.App. 729, 735, 383 N.W.2d 112 (1985). Contrary to respondent's argument, however, nothing in the APA or the Michigan Constitution precludes the Legislature from providing for review de novo in the circuit court. In fact, § 28 of article 6 of the constitution merely establishes the minimum review to be applied, without forbidding more stringent review, and the standard of review set forth at § 106 of the APA, expressly does not apply "when a statute ... provides for a different scope of review...."
We conclude that the language in M.C.L. § 400.725; M.S.A. § 16.610(75), providing that on appeal from an administrative agency decision under the act, the circuit court "shall have jurisdiction to hear and determine the questions of fact or law involved in the appeal," requires circuit courts to engage in a de novo standard of judicial review. This conclusion finds support in the Michigan Law Revision Commission's 25th Annual Report (1990), Attachment 1, p. 63. In the report, entitled "Judicial Review of Administrative Action", the commission recognized M.C.L. § 400.725; M.S.A. § 16.610(75) as establishing a de novo standard of review. The commission further discussed § 25 in an endnote to Attachment 1:
This [statute] is an example of using the contested case hearing provisions [of the APA], but not using the APA judicial review provisions. The method stated is to "appeal" by filing an affidavit and the venue is the circuit in which the person resides. The scope is apparently de novo, since the statute gives the court jurisdiction to hear and determine all questions of law and fact. [Id., p. 82, n. 129. Emphasis added.]
Although the circuit court erroneously concluded that the statute did not provide for a de novo standard of judicial review, the court indicated that it would, and did, affirm the administrative agency's findings of fact under a de novo standard of review. Accordingly, this issue does not provide a basis for reversal of the circuit court's decision in this case.

II
Petitioner next contends that it was deprived of certain procedural protections afforded a licensee before the administrative termination of a license. In this regard, petitioner argues that it received inadequate preliminary notice of the alleged violations and that it was denied the opportunity to comply, as required by memorandum DOP 84-05, which was promulgated to comply with the requirements of § 92 of the APA, M.C.L. § 24.292; M.S.A. § 3.560(192), and Rogers v. State Bd. of Cosmetology, 68 Mich.App. 751, 244 N.W.2d 20 (1976).
Section 503.7 of DOP 84-05 defines a refusal to renew as an adverse action to be used when a licensee has demonstrated a substantial and wilful noncompliance with the rules or the law. Section 92 provides that before commencement of proceedings to suspend, revoke, cancel, or amend a license, the licensee must be given an opportunity to show compliance with all lawful requirements for retention of the license.[1] In Rogers, supra, this Court held that a preliminary notice and informal opportunity to show compliance with licensing requirements must precede the notice and formal hearing in the proceedings to suspend, revoke, cancel, or amend the license. When an adverse action is taken, a four-step procedure, in accordance with the interpretation of § 92 of the APA in Rogers, supra, should be followed by the respondent before effecting a refusal to renew the terms or status of a license.
*204 Pursuant to DOP 84-05, § 503.7, the first step of the procedure requires that respondent send a notification letter of the "facts or conduct constituting the alleged violations of the act or rules." We have reviewed the record and find that the April 7, 1993, warning letter, which petitioner admitted receiving, sufficiently summarized all "the facts and conduct" of the alleged violations.
The second step, which evidently was not followed by respondent, provides that, in cases not involving "noncorrectable" licensing violations, the respondent should provide the licensee with the opportunity to show compliance by either correcting the violations or submitting an acceptable plan of correction, or showing that the violations did not occur. Correctable violations occur
[w]hen serious and willful violations of the act or rules or a pattern of ongoing noncompliance have been substantiated by the department's investigation, and the violations are such that they are correctable by the licensee.... [DOP 84-05, § 503.72.]
If compliance is demonstrated by the licensee, no further action is taken by the respondent. DOP 84-05, § 503.7.[2] (A noncorrectable violation is by its very nature, considered to be wilful and substantial.)
In petitioner's case, the April 7, 1993, warning letter only provided an opportunity to show compliance by demonstrating that the licensing violations did not occur. It failed to also include the option of showing compliance by correcting the violations or submitting an acceptable plan of correction. As a result, petitioner contends that, because the violations in this case did not involve "noncorrectable" violations and petitioner showed that all the violations were corrected, no further adverse action should have been taken by respondent.
In addressing this claim below, both the hearing referee and the circuit court noted that in Marrs v. Bd. of Medicine, 422 Mich. 688, 696, 375 N.W.2d 321 (1985), the Michigan Supreme Court rejected the proposition that § 92 of the APA allows a licensee to avoid an adverse license action whenever compliance is shown by correction of the license violations in question:
Dr. Marrs contends that upon his showing that the practices objected to had ceased and that there was no likelihood of repetition, the proceedings against him should have been dismissed. We agree with the Court of Appeals interpretation of the applicable statutory provision, that is, the purpose of the informal proceedings is to provide an opportunity to dispute unwarranted charges prior to the initiation of formal proceedings. Thus, M.C.L. § 24.292; M.S.A. § 3.560(192) is a procedural safeguard. We disagree with Dr. Marrs that upon a showing by the licensee that violations have ceased and that regulations will be followed in the future the board is required to dismiss the complaint. Although the board has the option of terminating proceedings, it is not obligated to do so.
Petitioner attempts to distinguish the Marrs decision by noting that the Marrs case did not involve any "rules ... equivalent to DOP 84-05," that the requirements of the APA yield to the requirements of the Adult Foster Care Facility Licensing Act and the "rules promulgated thereunder," and that the Marrs case did not involve a "two-year renewal requirement."
Petitioner's arguments, however, are not persuasive. First, respondent's internal policy manual, DOP 84-05, is not an administrative "rule" promulgated under the Adult Foster Care Facility Licensing Act. As noted by the hearing referee, the administrative rules promulgated under the act were specifically revised in 1984 to remove language that would allow licensees to retain their licenses by merely correcting any violations. Second, the fact that the act requires licensees to renew their licenses every two years is not a basis for distinguishing Marrs. Whether license violations result in premature revocation, suspension, or nonrenewal of a license, the requirements of § 92 of the APA remain the same.
*205 Finally, petitioner's claim that DOP 84-05 creates enforceable procedural due process rights, where § 92 of the APA does not, overlooks the fact that an administrative agency's unpromulgated interpretative statements or rules that merely interpret the underlying statutes or promulgated rules under which the agency operates have no force of law, and no sanction attaches to the violation of the interpretative statement or rule itself, but only to the violation of the underlying statute or promulgated rule. Boyd v. Civil Service Comm., 220 Mich.App. 226, 235-237, 559 N.W.2d 342 (1996). Moreover, a court may excuse a procedural deficiency if the rule in question merely assists the administrative agency in the exercise of its discretion and there is no substantial prejudice to the complaining party. West Bloomfield Hosp. v. Certificate of Need Bd., 452 Mich. 515, 524, 550 N.W.2d 223 (1996).
On the basis of the foregoing, we conclude that the fact that respondent arguably violated its internal rule by denying petitioner the opportunity to show at an informal hearing that it had corrected or had plans to correct the violations is not a basis for reversal. Marrs, supra.

III
Petitioner also argues that an adult services worker and a former county director were prejudiced by personal bias because of the ethnicity and higher education of petitioner's owner. Due process requires the right to an impartial decisionmaker. Crampton v. Dep't of State, 395 Mich. 347, 351, 235 N.W.2d 352 (1975); Michigan Intra-State Motor Tariff Bureau, Inc. v. Public Service Comm., 200 Mich.App. 381, 391, 504 N.W.2d 677 (1993). Petitioner, however, has failed to present any convincing evidence to support its allegations that it was denied renewal of its operating license because of bias and prejudice. As both the hearing referee and the circuit court found, petitioner's claims are purely speculative and unsupported by any evidence.

IV
Petitioner next contends that, because respondent previously renewed petitioner's license, respondent was estopped from claiming that any of the alleged license violations that occurred before petitioner's last license renewal in 1991 constituted wilful and substantial noncompliance. Thus, the hearing referee and the circuit court exceeded the scope of review by considering any of the pre-1991 violations. The only authority petitioner cites in support of this argument is an April 1993 proposal for decision and opinion of another hearing referee that recommended the reversal of a license revocation decision in another case, In re Greenville Acres Adult Care Home, Inc., in which the hearing referee stated:
Other matters were raised during the hearing, however, the tribunal ruled that because the department issued a regular license to Greenville in 1988 it could not allege violations as far back as 1985 were wilful or substantial and such allegations could not be considered as a basis for revoking the license in 1990.
However, as correctly noted by the hearing referee in this case, the Greenville case is distinguishable because no postrenewal violations were established in that case. Petitioner makes no attempt to address or refute the hearing referee's interpretation of the Greenville decision. "It is not enough for an appellant in his brief simply to announce a position or assert an error and then leave it up to this Court to discover and rationalize the basis for his claims, or unravel and elaborate for him his arguments, and then search for authority either to sustain or reject his position." Mitcham v. Detroit, 355 Mich. 182, 203, 94 N.W.2d 388 (1959). Moreover, the record supports that respondent also relied on numerous post-1991 violations, in refusing to renew petitioner's license. We therefore conclude that this claim does not provide a basis for reversal.

V
Finally, petitioner argues that the various postrenewal and prerenewal violations alleged in this case do not show that petitioner "willfully and substantially" committed the violations within the meaning of *206 M.C.L. § 400.722(1); M.S.A. § 16.610(72)(1).[3] Specifically, petitioner argues that the hearing referee's interpretation of the word "willfully" held petitioner to a negligent or strict liability standard because, under the definition, all the licensees should know the rules and the licensee is responsible for occurrences outside its control.
We initially note that many of the violations alleged in this case, such as the financial exploitation of a resident, the failure to provide medication, and the failure to provide dry clothing for a resident who was incontinent, involved much more than mere negligence on the part of petitioner's staff. As such, we find petitioner's argument on this point largely academic.
In any event, we find petitioner's claim that it did not wilfully violate the rules because it always corrected the cited violations unpersuasive. As the hearing referee found, although petitioner made certain facility improvements upon receiving citations or warnings, violations continued to occur. We further find that, contrary to petitioner's claim, the involved staff's misconduct was not beyond the control of petitioner's owner. As the hearing referee noted, although petitioner's owner was ill, he admitted being aware of the involved staff member's shortcomings as early as September 1992, yet left that person in charge of the facility until January 31, 1993, even though the owner apparently was well enough by late December 1993 to personally inspect the premises in response to the complaints being investigated at that time. We therefore conclude that reversal is not required on this basis.
Affirmed.
NOTES
[1]  In accordance with § 92 of the APA, DOP 84-05, § 503.71, provides an exemption to the requirement that a licensee be allowed to show compliance when respondent finds "that the public health, safety or welfare requires emergency action...." In this case, however, there is no indication that respondent considered this case as an emergency situation.
[2]  The first two steps of the four-step procedure are considered to be "informal" compliance procedures; only when a licensee has failed to show compliance are steps three and four, the "formal" steps, initiated. DOP 84-05, § 503.71.
[3]  M.C.L. § 400.722(1); M.S.A. § 16.610(72)(1) provides:

The department may deny, suspend, revoke, or refuse to renew a license, or modify a regular license to a provisional license, if the licensee falsifies information on the application for license or willfully and substantially violates this act, the rules promulgated under this act, or the terms of the license. [Emphasis added.]
