The respondent, John W. Cook, appeals an order of the Superior Court (Burling, J.) ordering him to pay $659.00 per month under the child support guidelines and refusing to give him credit for monthly payments of $762.00 in Social Security retirement dependency benefits received by the petitioner, Denise Angley-Cook, on their child’s behalf. We vacate and remand.
The parties divorced in 1993, with the petitioner retaining custody of their minor child. When the respondent turned sixty-five he began receiving Social Security retirement benefits and the petitioner began receiving Social Security retirement dependency benefits as payee on their child’s behalf. In 2002, the respondent petitioned the court to modify his child support obligation and pointed to the fact that the petitioner receives his Social Security retirement dependency benefits. He asked the court to give him a dollar-for-dollar credit for those benefits. The court ordered the respondent to pay $659.00 per month under the child support guidelines, and refused to consider the monthly payments of $762.00 in dependency benefits.
*258On appeal, the respondent argues that he should receive a dollar-for-dollar credit for those benefits under RSA chapter 458-C (1992 & Supp. 2003). We agree.
We review the trial court’s interpretation of a statute de novo. Monahan-Fortin Properties v. Town of Hudson, 148 N.H. 769, 771 (2002). In cases of statutory interpretation, we are the final arbiter of the legislature’s intent as expressed in the words of the statute considered as a whole. State v. McCarthy, 150 N.H. 389, 390 (2003). We ascribe to statutory words and phrases their usual and common meaning, unless the statute itself suggests otherwise. Id.
The respondent currently receives monthly Social Security retirement benefits from the Social Security Administration. The petitioner, as the custodial parent, receives a monthly payment on her child’s behalf directly from the Social Security Administration in the form of Social Security retirement dependency benefits. “These payments are referred to as ‘children’s insurance benefits’; they are an integral part of [the respondent’s] social security retirement benefits, and [the child’s] entitlement to them derives from [the respondent’s] eligibility [for] and past participation in the social security program.” Miller v. Miller, 890 P.2d 574, 576 (Alaska 1995); see 42 U.S.C. § 402(d)(2) (2000).
RSA 458-C:2, II provides that a parent’s “child support obligation” “means the proportion of total support obligation which the obligor parent is ordered to pay in money to the obligee parent as child support.” RSA chapter 458-C does not define what constitutes a payment in money, however, and it is not clear from the plain meaning of the statute whether a monthly payment that an obligee parent receives in the form of a dependency benefit constitutes a payment in money for the purposes of satisfying the obligor parent’s child support obligation. When the language of a statute is ambiguous, we construe it in light of the legislature’s intent in enacting it, and in light of the policy sought to be advanced by the entire statutory scheme. McCarthy, 150 N.H. at 391.
Although we have not yet addressed the issue of whether Social Security retirement dependency benefits received by a custodial parent should be credited against a noncustodial parent’s child support obligation, “[t]he overwhelming majority of states that have considered this issue allow a credit for Social Security benefits paid to dependent children.” Pontbriand v. Pontbriand, 622 A.2d 482, 484 (R.I. 1993); see also Rosenberg v. Merida, 697 N.E.2d 987, 990 (Mass. 1998); Miller, 890 P.2d at 576. While some cases that have dealt with Social Security dependency benefits have done so in the context of Social Security Disability Income dependency benefits, we see “no reason to treat retirement benefits any *259differently than disability benefits.” Miller, 890 P.2d at 577 (analyzing retirement dependency benefits); see also Rosenberg, 697 N.E.2d at 990 n. 4 (analyzing disability income dependency benefits). We choose to follow the majority of States and allow the obligor credit for his or her child support obligation as a per se rule. See Rosenberg, 697 N.E.2d at 990. We find persuasive, as the rationale for this position, that:
[U]nlike welfare and other forms of public assistance, social security benefits represent contributions that a worker has made throughout the course of employment....
... Although the benefits are payable directly to the child rather than through the contributing parent, the child’s entitlement to payments derives from the parent, and the payments themselves represent earnings from the parent’s past contributions.
Miller, 890 P.2d at 576-77; see also Rosenberg, 697 N.E.2d at 990. Allowing a credit to the noncustodial parent is not detrimental to the interests of the dependent child or children because once the proper support amount is determined under the guidelines, the actual source of the payments should be of no concern to the custodial parent, so long as the payments are actually made. Rosenberg, 697 N.E.2d at 990-91. Therefore, we find that Social Security retirement dependency benefits constitute a payment in money for the purposes of satisfying the obligor parent’s child support obligation under RSA 458-C:2, II.
Furthermore, the court shall consider the dependency benefits as gross income to the respondent when calculating his child support obligation. RSA 458-C:2, IV defines “gross income” as “all income from any source,” and explicitly lists social security benefits in the items that are to be included in income. RSA 458-0:2, IV (emphasis added); cf. Rosenberg, 697 N.E.2d at 991. As the petitioner states in her brief, “[T]he Legislature constructed a system based on parent’s current income.” “It thus seems clear that the guidelines contemplate that the [Social Security retirement dependency benefits] should be included in the income of one parent or the other.” Rosenberg, 697 N.E.2d at 991. We agree with the Massachusetts Supreme Judicial Court that “[t]he fairest approach for calculating the credit here is to treat the ... dependency benefits as if they were first paid directly to the noncustodial parent, who then pays that same amount to the custodial parent to satisfy some part of the support obligation.” Id. at 991.
We note that even if we were to decide that the Social Security retirement dependency benefits are not Social Security benefits as listed *260in the statute, they would nonetheless qualify as an “other government, program,” see RSA 458-C:2, IV, under the “gross income” provision of the child support guidelines, that is not specifically excluded as a “public assistance program”' because such benefits are not based upon a means-test. See In the Matter of Hennessey-Martin & Whitney, 151 N.H. 207, 210-11 (2004); Mathews v. De Castro, 429 U.S. 181, 185-86 (1976) (“The old-age and disability insurance aspects of the Social Security system do not purport to be general public assistance laws that simply pay money to those who need it most____Rather, the primary objective [is]- to provide workers and their families with basic protection against hardships created by the loss of earnings due to illness or old age.”).
Thus, “the amount of the ... dependency benefits should be included in the income of the noncustodial parent and the guidelines should then be applied to that amount.” Rosenberg, 697 N.E.2d at 991; see also Miller, 890 P.2d at 578. The noncustodial parent is then allowed a credit equal to the amount of the dependency benefits, and the net amount of the noncustodial parent’s support obligation is the difference between the support amount determined by the court to be correct under the guidelines minus the amount of the credit. See Rosenberg, 697 N.E.2d at 991. An exception exists if the support amount determined by the court to be correct under the guidelines is less than the dependency benefits. See id. at 991 n.7 “In such case, the total support obligation is simply equal to the amount of the ... dependency benefits, and the noncustodial parent would not owe any additional amount.” Id.
We find the petitioner’s argument regarding the federal anti-alienation provision, see 42 U.S.C.§ 407(a) (2000), to be without merit and warranting no further discussion. See Vogel v. Vogel, 137 N.H. 321, 322 (1993).
Wé vacate the trial court’s order and remand for findings not inconsistent with this opinion.
Vacated and remanded.
Nadeau, Duggan and Galway, JJ., concurred; Broderick, C.J., dissented.