concurring in part and dissenting in part.
{¶ 30} The overriding issue in this fact-intensive case is whether appellant, Montgomery County Children Services (“MCCS”), exercised “reasonable diligence” under Juv.R. 16(A) in attempting to serve appellee Iler Crawford with notice of a hearing in which his parental rights were at stake. In my view, the majority unjustifiably limits its analysis of that issue by resolving it solely within the narrow confines of a discussion of the requirements of Civ.R. 4.6(D). But this case also presents this court with an opportunity to clarify the standards that should apply to similar situations in the future. The majority fails to take advantage of the opportunity to provide sorely needed guidance on how a court should evaluate the validity of service by publication in a parental-rights case.
{¶ 31} For the reasons explained below, I dissent in part. I would vacate the judgment of the court of appeals and remand this cause to that court to apply Sizemore v. Smith (1983), 6 Ohio St.3d 330, 6 OBR 387, 453 N.E.2d 632, to all the relevant facts and circumstances.
I
{¶ 32} In In re Adoption of Walters, 112 Ohio St.3d 315, 2007-Ohio-7, 859 N.E.2d 545, ¶ 18, this court stressed that the right to raise a child is an essential and basic civil right. Furthermore, the United States Supreme Court has established that the right of a parent to the custody of his or her child is a fundamental liberty interest. Troxel v. Granville (2000), 530 U.S. 57, 65-66, 120 S.Ct. 2054, 147 L.Ed.2d 49. See also In re Murray (1990), 52 Ohio St.3d 155, 157, 556 N.E.2d 1169.
{¶ 33} Because this case implicates a parent’s constitutional right to the care and custody of his child, Crawford “ ‘must be afforded every procedural and substantive protection the law allows.’ ” In re Hayes (1997), 79 Ohio St.3d 46, 48, *416679 N.E.2d 680, quoting In re Smith (1991), 77 Ohio App.3d 1, 16, 601 N.E.2d 45. I readily acknowledge that Crawford has never exercised his parental rights or taken on any responsibilities with regard to Thompkins. However, although Crawford’s failings as a parent were relevant to the trial court’s determination whether permanent custody should be granted to MCCS, his parental deficiencies are irrelevant to the inquiry whether service of the notice of hearing to terminate his parental rights was valid. To answer that question, a reviewing court must focus only on the details of the service itself.
{¶ 34} When a dispute arises as to whether a party exercised reasonable diligence preceding resort to service by publication under Juv.R. 16(A), the burden is on that party to establish the reasonable diligence of its efforts. See In re Miller (1986), 33 Ohio App.3d 224, 226, 515 N.E.2d 635. Because service by publication is a method of last resort, the requirements of Juv.R. 16(A) are to be strictly enforced. See In re Wilson (1984), 21 Ohio App.3d 36, 40, 21 OBR 38, 486 N.E.2d 152.
{¶ 35} In perfecting service of notice on a person that a court proceeding is to take place and that the proceeding will affect the person’s fundamental rights in property or family, the most reliable method of notification is to have a process server hand the notice to the person. That form of service, however, is not always possible or practical, nor is it necessarily required by rule or statute.
{¶ 36} The next best method is to personally serve the notice at the residence of the individual by leaving it with a competent adult. When these methods of “personal” and “residence” service fail, the next preferred method is to send the notice by certified mail.
{¶ 37} The return of the receipt card signed by the person or another adult at the address signifies (certifies) that the mail was received, and thus, that document suffices to show “personal” service of notice of the proceeding.
{¶ 38} If the certified letter is returned, and the reason given to the sender for its failure to be delivered indicates that the letter was unclaimed, ordinary mail service to that same address is then proper. If a letter sent by ordinary mail service is not returned to the sender as undeliverable, then service is deemed to have been made upon the person.
{¶ 39} If, however, a certified letter is returned and indicates that the addressee is unknown at that address, it makes no sense to pursue ordinary mail service there because the addressee is known not to be at the address. Civ.R. 4.6(D) does not require an exercise in futility. Instead, the Civil Rules authorize service of notice by publication in a newspaper of general circulation in the county in which the action is pending.
*417{¶ 40} The resort to publication service requires the filing of an affidavit that avers that the party or his counsel exercised “reasonable diligence” to ascertain the address of the person to be served. Juv.R. 16(A). See also Civ.R. 4.4(A)(1). Service by publication cannot substitute for exercising reasonable diligence in ascertaining the current address of the person. This case must be analyzed by focusing on the reasonable diligence expended by MCCS to ascertain Crawford’s address.
{¶ 41} This court previously considered reasonable diligence under Civ.R. 4.4(A) in Sizemore v. Smith, 6 Ohio St.3d 330, 6 OBR 387, 453 N.E.2d 632.1 There, we emphasized that “what constitutes reasonable diligence will depend on the facts and circumstances of each particular case.” Id. at 332, 6 OBR 387, 453 N.E.2d 632. We further stated that “[Reasonable diligence requires taking steps which an individual of ordinary prudence would reasonably expect to be successful in locating a defendant’s address.” Id.
{¶ 42} In Sizemore, we gave examples of some steps that could be undertaken in the typical exercise of reasonable diligence, but we commented, “These examples do not constitute a mandatory checklist. Rather, they exemplify that reasonable diligence requires” the use of “common and readily available sources” in the search. Id.
{¶ 43} The resolution of this case depends on whether MCCS exercised “reasonable diligence” in attempting to serve Crawford. That inquiry requires a consideration of whether MCCS used reasonable diligence in attempting to ascertain Crawford’s current address, not simply whether the proper method of service was used. See id. at 331, 6 OBR 387, 453 N.E.2d 632. The court of appeals did not focus on whether MCCS exercised reasonable diligence in ascertaining Crawford’s address based on a consideration of all relevant facts and circumstances as required by Sizemore. Instead, it limited its inquiry to whether service by ordinary mail to the Columbus address was required under Civ.R. 4.6(D). This approach unjustifiably concentrated on one small factor and abandoned the larger inquiry.
{¶ 44} It is apparent that a failed attempt at service indicated by certified mail returned marked “Attempted Not Known” is different from a failed attempt at service indicated by certified mail returned marked “unclaimed.” Although Civ.R. 4.6(D) specifies the procedures to be followed when “unclaimed” certified mail is involved, it is not at all clear that those same procedures come into play when certified mail is returned marked “Attempted Not Known.” In part, this is *418because that phrase is not used within the civil rule and is ambiguous in this situation.2 I therefore conclude that Civ.R. 4.6(D) did not necessarily mandate ordinary mail service in this situation, and so agree with the majority on that point.3
{¶ 45} This case involves the termination of parental rights, and therefore a comprehensive consideration of whether MCCS established reasonable diligence is especially appropriate here. Because the court of appeals did not conduct such an inquiry, its judgment is incomplete. The proper course at this point is to vacate that judgment and remand the cause to the court of appeals for a full consideration of all facts and circumstances in accordance with Sizemore.
II
{¶ 46} Although there are a large number of competing concerns that I believe should be considered and addressed by the court of appeals, there are three critical facts in the record that I believe warrant special attention.
{¶ 47} First, when service regarding the first hearing, which was scheduled to occur on January 15, 2003, was attempted on Crawford at his mother’s house in Dayton, his mother accepted service on his behalf on December 28, 2002. The summons’s return-of-service form bore the typewritten statement that “residential service” was made “upon_by leaving a copy of the summons and accompanying document(s) at his/her usual place of residence.” On the blank line within the statement, “Iler Crawford” had been printed by hand.
{¶ 48} Second, after a new complaint was filed and the case was assigned a new case number, a hearing was scheduled for April 14, 2003. Service regarding that hearing was attempted on Crawford at the same house in Dayton in March 2003. At the bottom of the identical return-of-service form, the process server wrote that he was unable to serve Crawford because Crawford “had not lived at [that] address for almost a year.” (Emphasis added.)
*419{¶ 49} Third, the “reasonable diligence” affidavit filed by MCCS on March 13, 2003, which was to support the resort to service by publication, detailed that Crawford’s residence was unknown and that his last known addresses were one in Columbus (the address at which certified mail service was later attempted) and his mother’s address in Dayton.
{¶ 50} The affidavit also stated that MCCS checked criminal databases (CRISE, Prison Locator; Montgomery County Jail; Ohio Defender Database) in a “diligent search”; that letters had been sent to the Columbus address but that they had been returned; that service was “made residential” under the case number for the first hearing, “as service was accepted by” Crawford’s mother; that after the complaint was refiled, service was again attempted at the mother’s address but that “[t]he process server was told that the father has not lived at that address in a year”; that contact was attempted with family members at the mother’s address but that no response was received; and that “MCCS knows of no other addresses for the legal father.” The affidavit concluded, “The residence of the legal father cannot be ascertained with reasonable diligence and service should be made by publication as provided by law.”
{¶ 51} Despite MCCS’s assertion that reasonable diligence was established, an examination of the three facts noted above reveals that that fundamental assumption could be erroneous.
{¶ 52} The note on the March summons’s return of service indicating that Crawford had not lived at his mother’s house “for almost a year” directly contradicts the language on the December summons’s return of service that indicated that his mother’s address was Crawford’s “usual place of residence.” In addition, as clarified by the statement of the process server regarding the March service attempt, it appears that the December service attempt had not been “successful” after all. And if the December service attempt was not successful, then there would be no reason to expect success in the March service attempt.
{¶ 53} Arguably, the contradictions suggested by the service record and the reasonable-diligence affidavit should have alerted MCCS of the need to conduct a new “diligent search.” The process server’s notes about the lack of success in serving Crawford in Dayton established that that address was not correct. Several letters (apparently by ordinary mail) had been sent to the Columbus address and had been returned by the post office. MCCS attempted to achieve service by certified mail at the Columbus address only in an after-the-fact effort that commenced after notice by publication in Dayton had occurred. Clearly, MCCS did not believe that the Columbus address was a likely one for Crawford. And evidently, MCCS did not find Crawford in any criminal database that would have shown him to be in state custody. Thus, Crawford was at another address.
*420{¶ 54} It is not for this court to conduct its own consideration of the full record to determine whether MCCS acted with reasonable diligence in ascertaining Crawford’s address. That is a review that should be conducted by the court of appeals. The considerations cited are solely to illustrate that the inquiry is a fact-intensive one that cannot be resolved simply by addressing one specific concern.
Ill
{¶ 55} The majority opinion pays lip service to the due process concerns that are implicated in this case by recognizing that parents (even those, such as Crawford, who make no attempt to fulfill their parental responsibilities) must be afforded a high level of both procedural and substantive protections. Because service by publication is a service method of last resort that frequently fails to provide a party actual notice of impending proceedings, heightened scrutiny of that service method is especially important in parental-rights cases. But heightened scrutiny can be achieved only if clear standards are set and are applied in evaluating the validity of service on a particular person in a particular situation. Furthermore, when a reviewing court assesses a trial court’s conclusion that service by publication was proper, the reviewing court should apply the same standards, and should not defer to the trial court’s conclusion.
{¶ 56} I would take advantage of the opportunity presented by this case to hold that when parental rights are at stake, a reviewing court has a duty to conduct a de novo analysis of the validity of service. I would hold that this analysis should be done even when, as here, the service issues are presented to the court of appeals in a somewhat limited form and the parent has shown no interest in the child.
{¶ 57} In determining that service by publication was adequate in this case, the magistrate and trial court considered some of the factors discussed in Sizemore, but neither cited any rules, statutes, or case law as standards to guide their considerations. In reviewing the conclusion that service was proper, the court of appeals recognized a heightened duty to thoroughly examine the situation in light of the entire record, commenting that “parental rights are fundamental, and may not be terminated without due process.”
{¶ 58} As explained above, I agree with the majority that the court of appeals incorrectly reversed the trial court’s judgment on Civ.R. 4.6(D) grounds. However, because I believe that the court of appeals truncated its analysis by focusing on the specifics of Civ.R. 4.6(D) and then stopping once it determined that that rule had not been complied with, I disagree with the majority’s decision to simply reverse the judgment of the court of appeals and reinstate the trial court’s determination that service was proper. I would remand the cause to the court of appeals to complete its analysis.
Mathias H. Heck Jr., Montgomery County Prosecuting Attorney, and Jennifer B. Frederick, Assistant Prosecuting Attorney, for appellant. D.K. Wehner, for appellee.{¶ 59} For the foregoing reasons, I would vacate the judgment of the court of appeals and remand this cause to that court for consideration whether, in light of all the relevant facts and circumstances, MCCS met its burden of establishing that it exercised “reasonable diligence” under the standards discussed in Size-more.
Moyer, C.J., and Pfeifer, J., concur in the foregoing opinion.. Sizemore was not an appeal from a juvenile court’s decision, so Juv.R. 16 was not at issue in that case. However, because Juv.R. 16(A)’s relevant provisions on service by publication parallel the pertinent provisions of Civ.R. 4.4(A) analyzed in Sizemore, this court’s discussion of reasonable diligence in Sizemore is fully applicable here.
. Other courts have encountered the term “attempted not known,” but there does not appear to be a consensus on a specific meaning. See, e.g., Jefferson Cty. Treasurer v. Brown, Jefferson Cty. App. No. 04 JE 30, 2005-Ohio-2933, 2005 WL 1385729, ¶ 30 (suggestion that “attempted not known” means an attempted delivery but the named recipient was not present); Adams v. Commr. of Internal Revenue (T.C.1994), 1994 WL 397318, *2 (“the notation ‘Returned to Sender, Attempted, Not Known’ means that the Postal Service carrier attempted delivery and was told at the point of delivery that the addressee did not live there”).
. The attempted service by certified mail on Crawford at the Columbus address was an attempt to obtain service after the publication of notice had already occurred in Dayton and thus could be viewed as merely an after-the-fact attempt to cure earlier deficient efforts at service. It is not an extremely important fact in the overall efforts to obtain service. In focusing extensively on a possible follow-up attempt at service at the Columbus address by ordinary mail, the court of appeals placed undue emphasis on a fact that may not have any import.