Appellant, Johnnie Brown, challenges a trial court order following a bench trial denying his claims against the estate of his sister, Sarah Key. Appellant filed separate claims for personal services rendered and money spent on her behalf before her death. We agree with appellant that the trial court applied an incorrect legal standard in deciding his claims for services rendered. Moreover, the trial court failed to address appellant’s claim for money spent on behalf of Ms. Key. We therefore must reverse and remand for further consideration.
I.
Sarah Key died on August 28, 1984 after a long illness. Before her death she had been confined at Howard University Hospital on two separate occasions for lengthy periods of time. While Ms. Key was in the hospital, appellant had looked after her home. Upon Ms. Key’s last release from the hospital in early May 1984, appellant had left his home and moved into hers to provide the full-time nursing care his sister required. Appellant testified that, except for doing necessary errands, he had remained at his sister’s home continuously, meaning 24 hours a day, until she died three and a half months later. Appellant claimed he had paid his sister’s bills, including funeral expenses, cooked her meals, cleaned the house, done the laundry, changed her bedpan, and had provided other practical nursing care. After Ms. Key’s death, appellant filed a claim with the estate’s personal representative totaling $10,-000 for personal services plus $1,118 representing the amount appellant allegedly had spent on Ms. Key’s behalf.1 Appellant filed his claim after discovering he had not been named a beneficiary in his sister’s will.
At trial, appellant testified that he had performed the services pursuant to an oral contract with his sister. According to appellant, Ms. Key had promised to pay him for his services sometime in the future. He further testified that she had asked him to stay with her after she left the hospital and had reassured him that he would “be well paid.”
Appellant attempted to corroborate the existence of this alleged contract with the testimony of several of his sister’s neighbors, who indicated that Ms. Key had told them appellant would be rewarded for his help. May Warren testified that, shortly before Ms. Key’s death, she had told Warren that appellant was taking care of her and would be paid well for his actions. Bilbo Clayborn, Ms. Key’s next door neighbor, testified that the decedent had told him “she would see that he [appellant] got paid for his time.” On cross-examination, however, Mr. Clayborn could not recall the specific date of this conversation, and he admitted that Ms. Key had not indicated how much she would pay appellant. Mrs. *1186Arnold, another neighbor, testified that Ms. Key had told her, in appellant’s presence, that appellant would be paid “for all the things he had ever done for her.” Mrs. Arnold, too, admitted that Ms. Key had not mentioned any specific sum she would give to appellant. Nor had she said when she would pay him. Finally, Shirley Marie Nelson, a friend of the decedent’s, testified that Ms. Key had told her she was going to change her will to compensate appellant for the money he had spent on her and the things he had done for her.
Appellee Brown, the personal representative of Sarah Key’s estate, presented the testimony of two witnesses, one of whom stated that Ms. Key had told her she would only leave her property to appellant as a “last resort.” The other witness testified that, for many years, she had assisted Ms. Key with her bills and that Ms. Key usually had had money left over each month after payment of all her bills.
In its post-trial order, the trial court denied appellant’s claim for compensation for services rendered. Relying on a presumption that services rendered by one family member to another are gratuitous in the absence of conclusive evidence of an agreement to pay, the trial court found that appellant “offered no convincing corroborating evidence to prove the existence of an agreement with his sister.” The trial court did not address appellant’s claim for money
spent on behalf of his sister. See supra note 1.
II.
With respect to his claim for personal services, appellant asserts several grounds for reversal. Only one of these, however, merits substantial discussion. Appellant challenges the court’s reliance on a presumption that services rendered by one sibling to another are intended to be gratuitous.2
A.
We note at the outset that ordinarily, in the absence of a close family relationship, a promise to pay will be implied in law when one party renders valuable services that the other party knowingly and voluntarily accepts. E.g., Zaleski v. Congregation of the Sacred Hearts of Jesus and Mary, 256 A.2d 424 (D.C.1969). Actually, a claim based on a contract implied in law (sometimes called a quasi-contract) “is not a contract [claim] at all, but [results from] a duty trust under certain conditions upon one party to require another in order to avoid the former’s unjust enrichment.” Bloomgarden v. Coyer, 156 U.S. App.D.C. 109, 116, 479 F.2d 201, 208 (1973) (footnote omitted) (adopted in H.G. Smithy Co. v. Washington Medical Center, 374 A.2d 891, 893 (D.C.1977); see also TVL Associates v. A & M Construction Corp., 474 A.2d 156, *1187159 (D.C.1984). When, however, there is an applicable presumption that the services were rendered gratuitously — as occurs, for example, in the context of a parent-child relationship, see Tuohy v. Trail, 19 App. D.C. 79 (1901) — a promise to pay obviously cannot be implied by the mere rendition and acceptance of valuable services. The presumption itself, as a matter of law, negates any implication that “it would be unjust0 for the recipient to retain the benefit conferred” without paying for it. H.G. Smithy Co., 374 A.2d at 895; see also Farrin v. Harlow, 62 App.D.C. 314, 67 F.2d 580 (1933) (where plaintiffs rendered nursing services for eleven years to decedent, to whom they were not related but with whom they lived as a family, court, without explicitly invoking presumption, concluded services were gratuitous, not contractual). It follows, then, that when a presumption of gratuity is applicable — as the trial court held in this case — a claimant may only recover, if at all, by rebutting that presumption with evidence of an express contract or a contract implied in fact.
B.
We turn, therefore, to the question whether the trial court was correct in premising this case on a presumption of gratuity. In Tuohy, 19 App.D.C. at 87, the court held that when a daughter performs services for her father there is a rebuttable presumption that the parties did not intend payment for those services. Such services are presumed to be gratuitous, and thus a promise to pay is not implied by the mere rendition of the services by one party and their acceptance by the other. Annotation, Recovery For Services Rendered By Member of Family, 7 A.L.R.2d 8, 15 (1949). The rationale behind this presumption was aptly summarized by the Arkansas Supreme Court in Capps v. Cline:
Such services are enjoined by the reciprocal duties of the family relation, and are always presumed to have been prompted by natural love rather than by the promise or the hope of pecuniary reward. “Courts are reluctant to infer a pecuniary recompense from performance of filial or parental duties such as humanity enjoins.” Hence the burden is upon [the person] who claims a money recompense for personal services performed, whether voluntarily, or upon the request of the other, to establish a contract expressed or implied for such consideration.
227 Ark. 201, 203, 297 S.W.2d 654, 655 (1957) (quoting Williams v. Walden, 82 Ark. 136, 141, 100 S.W. 898, 900 (1907); see also 66 Am.Jur.2d Restitution and Implied Contracts § 31 (1973).
Although Tuohy concerned services performed in the context of a father-daughter relationship, we conclude that the same analysis applies to services rendered by one sibling for another. While it is true, of course, that as the family relationship becomes more remote there is a lesser likelihood that services will be given without expectation of payment, we believe the sibling relationship is inherently close enough to sustain the presumption that services by a brother for an ailing sister, and vice versa, are rendered gratuitously. See, e.g., Capps, 227 Ark. at 203, 297 S.W.2d at 655; Lamb v. Jones, 202 So.2d 810, 815 (Fla.Dist.Ct.App.1967); In re Estate of Hill, 88 Ill.App.3d 1038, 1039, 44 Ill.Dec. 171, 173, 411 N.E.2d 77, 79 (1980); In re Estate of Clausen, 51 Ill.App.3d 18, 9 Ill.Dec. 48, 366 N.E.2d 162 (1977); In re Estate of Raketti, 340 N.W.2d 894, 902 (N.D.1983); Salmon v. Salmon, 406 S.W.2d 949 (Tex.Civ.App.1966). This approach is especially important in light of the fact that, absent a presumption of gratuity, there is a virtual presumption of a (quasi) contract — a contract implied in law — premised on unjust enrichment theory. We therefore reject authorities holding such a presumption does not necessarily apply to a brother-sister relationship. See Gibson v. McCraw, 332 S.E.2d 269, 273 (W.Va.1985); Annotation, Recovery For Services Rendered by Member of Family, 7 A.L.R.2d 8, 103 (1949) (citing cases); 66 Am.Jur.2d Restitution and Implied Contracts § 53 (1973) (“The mere relation existing between brothers, sisters, or brother and sister, is not sufficient to authorize a presumption that services performed by one for the other are gratuitous”).
*1188We agree with the Supreme Court of North Dakota that, “[r]ather than affecting the ‘strength’ of the presumption, the degree and nature of the family relationship [between brother and sister] are factors which may be considered in determining whether or not an implied agreement for compensation existed.” In re Estate of Raketti, 340 N.W.2d at 902 (footnote omitted). While we, too, realize that “this may very well lead to the same result as holding that the presumption grows weaker as the family relationship becomes more remote,” we believe “it is better to say that the presumption unconditionally shifts the burden [of persuasion to the claimant], and the nature and degree of the relationship are factors to be considered in determining whether or not the claimant has satisfactorily rebutted the presumption.” Id. at 902 n. 5.
Because the presumption of gratuitous services between siblings shifts the burden of persuasion, it is not premised on “the ‘bursting bubble’ theory”; it does not “place[] on the opponent only the burden of production of evidence” which, if satisfied, causes the presumption to vanish. Green v. District of Columbia Department of Employment Services, 499 A.2d 870, 874 (D.C.1985). Although the “bursting bubble theory is ‘the prevailing view, to which jurists preponderantly have subscribed’ ” in characterizing particular presumptions, Green, 499 A.2d at 874 (quoting Legille v. Dann, 178 U.S.App.D.C. 78, 83, 544 F.2d 1, 6 (1976)), this court, on several occasions, has recognized exceptions. In Green, for example, we recently held that under the Unemployment Compensation Act, D.C.Code §§ 46-101 to 46-127 (1981), the employer bears the burden of persuasion in proving that an employee voluntarily left his or her job and thus is not entitled to benefits.3
As in Green, “[substantial policy considerations,” 499 A.2d at 875, underlie the presumption that services rendered between siblings are gratuitous. We believe that, as a matter of common human experience, such services are usually performed out of a sense of family responsibility, not pursuant to a contractual agreement with the legitimate expectation of payment. If we were to employ only a “bursting bubble” presumption (which has no evidentiary weight once rebutted by some evidence to the contrary), that approach could lead too readily to a finding that a contract existed when, because of the sibling relationship, none was intended; once the bubble was burst, little if anything would prevent a conclusion that a contract was implied in law.4
C.
We turn next to rebuttal of the presumption. It “may be overthrown, and the reverse established by proof of an express or implied contract to that effect; an implied contract being proven by facts and circumstances which show that both parties, at the time the services were performed, contemplated or intended pecuniary recompense.” Tuohy, 19 App.D.C. at 87.5 Neither in Tuohy, however, nor in any other case we have been able to find has a court *1189of this jurisdiction articulated the quantum of proof necessary to rebut the presumption that services rendered to a close, adult relative are gratuitous.6 Moreover, our review of decisions elsewhere reveals a variety of approaches reflecting a considerable degree of confusion about this issue. See 66 Am.Jur.2d Restitution and Implied Contracts § 44 (1973) (citing cases). The quantum of proof necessary to rebut the presumption of gratuity has been described, for example, as “clear and convincing,” Gibson v. McCraw, 332 S.E.2d at 276; Brassfield v. Allwood, 557 S.W.2d 674, 681 (Mo.App.1977); Vosburg v. Smith, 272 5.W.2d 297, 301 (Mo.App.1954), a “preponderance of the evidence,” In re Estate of Clausen, 51 Ill.App.3d at 21, 9 Ill.Dec. at 50, 366 N.E.2d at 164; see also In re Estate of Steffes, 95 Wis.2d 490, 502 & n. 12, 290 N.W.2d 697, 703 & n. 12 (1980), a “showing of facts disclosing a different state of affairs,” Worley v. Worley, 388 So.2d 502, 507 (Ala.1980), and “sufficient evidence tending to establish a contract for remuneration,” In re Estate of Bouma, 206 Neb. 209, 211, 292 N.W.2d 37, 38 (1980). See also supra note 4.
Having reviewed the various approaches, we conclude that a claimant against a sibling’s estate for the reasonable value of services performed for that sibling during his or her lifetime should have the burden to demonstrate, by a preponderance of the evidence, In re Estate of Clausen, 51 Ill.App.3d at 21, 9 Ill.Dec. at 50, 366 N.E.2d at 164,7 the existence of either an express or implied agreement that he or she expected to be paid and that the decedent intended to make payment. Tuohy, 19 App.D.C. at 87; In re Estate of Raketti, 340 N.W.2d at 902; Campion v. Tennes, 93 Ill.App.3d 597, 602, 49 Ill.Dec. 58, 62, 417 N.E.2d 748, 752 (1981) (quoting Switzer v. Kee, 146 Ill. 577, 581, 35 N.E. 160, 162 (1893)); In re Estate of Hill, 88 Ill.App.3d at 1041, 44 Ill.Dec. at 174, 411 N.E.2d at 80; supra note 5. Thus, we reject the approach requiring a claimant to prove the existence of an agreement by “clear and convincing” evidence. See, e.g., Gibson, 332 S.E.2d at 276; Brassfield, 557 S.W.2d at 681; Vosburg, 272 S.W.2d at 301.8 Al*1190though we apply the presumption of gratuity primarily out of a belief that the very existence of a brother-sister relationship, without regard to its actual workings, should be enough to eliminate claims based on a contract implied in law (quasi-contract), we perceive no basis for imposing an additional requirement that the claimant must rebut the presumption by presenting “clear and convincing” evidence of a contract. Family members may be less likely than others to formalize contractual arrangements between themselves, even when remuneration is intended; thus, many if not most family contracts are likely to be implied in fact, not express. Requiring claimants to produce “clear and convincing” evidence of a contract, therefore, would create too difficult a barrier for recovery where it is merited, indeed a barrier higher than is common in civil litigation. See Green, 499 A. 2d at 877 (under unemployment compensation regulations, quantum of proof required to satisfy employer’s burden to prove employee voluntarily quit job “is, as in most civil cases, a fair preponderance of the evidence”).
D.
Because there is no express contract here, we next consider what a claimant must show in order to carry the burden of proving, by a preponderance of the evidence, the existence of a contract implied in fact. We have previously set out the general requirements for obtaining recovery on a quantum meruit theory under a contract implied in fact:
(1) valuable services must be rendered [by the plaintiff]; (2) for the person sought to be charged; (3) which services were accepted by the person sought to be charged, and enjoyed by him or her; and (4) under such circumstances as reasonably notified the person sought to be charged that the plaintiff, in performing such services, expected to be paid. TVL Associates, 474 A.2d at 159 (quoting In re Rich, 337 A.2d 764, 766 (D.C.1975)); see also H.G. Smithy Co., 374 A.2d at 893; Waco Scaffold & Shoring Co. v. 425 Eye Street Associates, 355 A.2d 780, 783 (D.C. 1976); Bloomgarden, 156 U.S.App.D.C. at 116-17, 479 F.2d at 208-09.
Where the presumption of gratuity applies, the determinative issue usually will be: whether the claimant has reasonably notified the other party, who presumably expects free services, of a clear enough expectation of payment that the recipient’s intention to pay can be inferred from acceptance of the services. In evaluating whether the claimant has sustained the burden of persuasion as to the existence of a contract, the factfinder must consider the totality of the circumstances. Such factors as the length of time during which services were performed, the nature of those services, and the respective financial statuses of the parties are relevant. See, e.g., Capps, 227 Ark. at 204, 297 S.W.2d at 656 (upholding jury verdict for claimant and pointing to uncontroverted evidence that claimant performed burdensome, extraordinary services over period of ten years); In re Estate of Clausen, 51 Ill.App.3d at 21, 9 Ill.Dee. at 50, 366 N.E.2d at 164 (upholding jury verdict for claimant taking into account that decedent’s estate was enhanced by receipt of claimant’s welfare checks and avoidance of nursing home expenses, claimant performed extraordinary services that were very burdensome, decedent stated he would pay claimant well, and claimant had no assets); In re Estate of White, 15 Ill. App.3d 200, 201-02, 303 N.E.2d 569, 571-72 (1973) (listing factors). Because the key question is whether, under the particular circumstances, the parties intended that compensation be paid, the result necessarily will hinge on the facts of each case. In re Estate of Raketti, 340 N.W.2d at 902.
*1191We turn now to whether the trial court applied the law correctly. The trial court’s order makes clear that the court required appellant to show by “clear and convincing” evidence that there was an express or implied contract between appellant and Ms. Key:
The general rule in this jurisdiction is that a promise to pay for services rendered by one family member to another will not be implied from the mere rendition of the services. Rather, it is held that the services are presumed to be gratuitous absent clear and distinct proof of an express [or implied] agreement to pay. [ (emphasis added) (citation omitted) ].9
This reference to a burden of proof higher than a preponderance of the evidence was not an isolated trial court comment; it unquestionably expressed the court’s view of the applicable standard. At a later point in its order, for example, the trial court commented on appellant’s evidence:
Here, Mr. Brown offered no convincing corroborating evidence to prove the existence of an agreement with his sister. He provided no indication that they had discussed the amount of compensation or the hourly rate and, as such, provided no clear and distinct proof of an express or implied contract to pay. [ (Emphasis added) ].
We are therefore persuaded that the trial court applied an improper standard of proof. Cf. Waco Scaffold, 355 A.2d at 783 n. 7 (isolated remark by trial court that appellant failed to prove case by “convincing proof” not sufficient to persuade this court that trial court had applied incorrect standard). Because we cannot say, based on the preponderance-of-evidence standard, that appellant has presented insufficient evidence as a matter of law to support his claim, we must remand for the trial court to apply the correct legal standard to the evidence before it.10 We wish to emphasize, however, that our remand should not be construed as a comment on the persuasiveness of appellant’s case. We express no view as to whether appellant has sustained the applicable burden of persuasion.11
III.
Finally, appellant argues that the trial court completely ignored his claims for money spent on behalf of his sister. Although there may have been no agreement to pay appellant for his services, it is conceivable that Ms. Key agreed to reimburse him for out-of-pocket expenses. Accordingly, this claim must be addressed separately.
Appellant is correct in pointing out that the trial court did not address this claim at all in its order. We therefore must remand for the trial court to do so. On remand, the court must first determine whether appellant used his own funds on his sister’s behalf, as he claims.12 If the trial court finds that he did so, the court should then divide the claim into two parts: money spent while Ms. Key was still alive (mortgage payment and nursing care), and money spent following Ms. Key’s death (funeral expenses). See supra note 1. With respect to the mortgage payment and nursing care, we see no reason why the same presumption of gratuity that applies to services between brother and sister should not also apply to support payments. See In re Estate of Hill, 88 Ill.App.3d at 1039, 44 Ill.Dec. at 173, 411 N.E.2d at 79.
*1192With respect to the funeral expenses, however, this presumption should not apply. Any expenditure following Ms. Key’s death is qualitatively different from support payments made during her lifetime and thus cannot be said to fall within the presumption of gratuity. Because we do not know whether the trial court, on remand, will find that appellant paid funeral expenses, we do not address that issue further.
Reversed and remanded.