Petitioner John M. Van Fossen appeals the refusal by the Merit Systems Protection Board (MSPB or Board), Docket No. PH075283A0109ADD, to award attorney fees incurred in his largely successful challenge of a removal action brought against him by his employer, the Department of Housing and Urban Development (HUD or agency). We reverse and remand.
I.
The facts concerning petitioner’s discharge (involving his outside work) can be found in this court's opinion, Van Fossen v. Department of Housing and Urban Development, 748 F.2d 1579 (1984), vacating the final decision of the Board (sustaining Van Fossen’s removal)1 and remanding to the Board to consider mitigating factors in determining an appropriate penalty other than removal. On remand, the Board affirmed the initial decision but concluded that “in light of ... mitigating circumstances [discussed in this court’s earlier opinion, supra; see also infra ] we find that the maximum reasonable penalty is a thirty-day suspension.”2 Petitioner then filed a fee petition for an award of attorney fees under 5 U.S.C. § 7701(g)(1).3 The offi*749cial who presided over petitioner’s removal action found that fees were incurred and ruled that Van Fossen was a prevailing party, but denied any award as not warranted in the interest of justice. The presiding official noted that neither this court nor the Board on remand held that Van Fossen had not violated the agency’s standards of conduct. She therefore concluded that petitioner was not entitled to an award of fees in the interest of justice under any of the Allen guidelines.4 Responding to petitioner’s claim that he was entitled to fees because he was substantially innocent of the charges, the presiding official cited without explanation “the general rule that an award of attorney fees is not merited in the interest of justice when the [petitioner] is found to have committed some misconduct.”
II.
The dispositive question presented to us on this appeal is whether petitioner was substantially innocent of the charges and therefore entitled to an award of attorney fees in the interest of justice even though all the charges against him were sustained by the Board and not voided by this court.5
We have previously discussed the second Allen category and its “substantially innocent” criterion in Sterner v. Department of the Navy, 711 F.2d 1563, 1569-1571 (Fed.Cir.1983); Sims v. Department of the Navy, 711 F.2d 1578, 1581-83 (Fed.Cir. 1983); Yorkshire v. Merit Systems Protection Board, 746 F.2d 1454, 1456-59 (Fed. Cir.1984); Thomson v. Merit Systems Protection Board, 772 F.2d 879, 881-82 (Fed. Cir.1985); Wise v. Merit Systems Protection Board, 780 F.2d 997, 999-1001 (Fed. Cir.1985); and Boese v. Department of the Air Force, 784 F.2d 388, 390-91 (Fed.Cir. 1986). Those cases make it clear that “substantial innocence” is an operative Allen guideline in and of itself. See, e.g., Boese, at 390-91. In Yorkshire, 746 F.2d at 1457, we noted, too, that the substantial innocence category serves a compensatory function, and is not punitive. This standard reflects Congressional awareness that the significant and often prohibitive expenses related to the defense of adverse actions discourage federal employees from challenging adverse agency action. Without the prospect of an award of attorney fees under the substantial innocence category, many employees would be forced to accept their removal without dispute since a successful challenge would leave them severely in debt, and possibly worse off than if they had not challenged their removal in the first place.
Of course, economic hardship by itself is insufficient to establish an award of fees in the interest of justice. Sterner, 711 F.2d at 1570. Rather, “the extent of a party’s victory” and “the magnitude of the injustice done the employee” are controlling considerations. Id. at 1567-68. More specifically, “the qualification ‘substantial’ (in the criterion of ‘substantial innocence’) connotes innocence of the more important and greater part of the original charges.” Boese, at 391.
Because a substantial innocence determination necessarily turns upon the result of the particular case, Yorkshire, 746 F.2d at 1457, we examine briefly the Board’s decision on remand from this court. The Board stated that:
*750[petitioner] made a good faith effort to follow the regulations, there is no indication that the proper authority would have withheld permission, and [petitioner] reasonably relied on the authorization memorandum for more than four years. Further, there was no monetary loss to the government and no actual conflict of interest. [Petitioner] fully cooperated with the investigation, and on the demand of his supervisor, promptly terminated his outside work. Moreover, there is no evidence indicating that there was any public awareness of [petitioner’s] outside activities or whether they were properly authorized. [Petitioner’s] personnel file is unblemished, and with almost twenty years of federal service, [petitioner] had not taken one day of sick leave. In light of these mitigating circumstances, we find that the maximum reasonable penalty is a thirty-day suspension.
It is true that all three charges against petitioner were sustained. However, the lead charge (engaging in outside employment without authorization) was based on a purely technical violation of an agency regulation — petitioner received his authorizing memorandum from the wrong individual (the area manager) in the agency’s hierarchy. In this connection, “[n]ot only did [Van Fossen’s co-workers] apparently believe this was the appropriate procedure, the area manager himself testified that he believed he had the authority [and in turn acted upon that authority] to grant approval.” Van Fossen, 748 F.2d at 1580-81. Moreover, the second charge of engaging in unauthorized outside activity was wholly dependent on the technical violation of receiving authorization from the incorrect official. And the third charge of not filing a report of his outside income was mentioned by the Board (in its opinion and order on remand) only in briefly summarizing the three charges. In sum, the Board itself did not on remand consider any. of the charges, though sustained, as serious or significant.
The gravity and circumstances of the offenses sustained are important factors in determining whether and to what extent fees should be allowed. We must reject the Board’s rigid and simplistic argument that because all the charges against petitioner were sustained, he cannot be considered substantially innocent for the purpose of awarding attorney fees under the interest of justice mandate. That mechanical position disregards the nature and weight of the particular offenses, and treats fleas as always the equivalent of elephants. That has not been this court’s rule or understanding in fee cases. In Sims, 711 F.2d at 1582, a mitigation case in which we upheld a denial of fees, we indicated that the sustained charges “concerned indisputably improper conduct.”6 In Boese, at 391, in allowing fees, we distinguished between the major and primary charge on which the employee was vindicated and the minor and secondary charge which was upheld.
Indeed, the MSPB has itself taken account of the nature of the sustained charges and awarded fees in circumstances very similar to those present here. See Filip v. Veterans Administration, 22 M.S. P.R. 642, 644 (1984), in which the Board held that where “the only charge sustained involved an agency regulation which previously had not been enforced and which had in fact been violated by appellant’s own supervisors,” the employee was substantially innocent. In Filip the Board did not, as it did here, merely perform simple arith*751metic in determining whether the employee was substantially innocent; it properly examined the substance, nature, and weight of the sustained charge, finding there that the sustained charge was only for a “technical violation.” The presiding official in this case wholly failed to make that type of evaluation. Nor did she give any weight at all — as she should have done — to the Board’s remand decision and the contents of that opinion and order.
Because the charges sustained were technical and very minor, and because the original drastic penalty of removal was significantly mitigated to the minor penalty of a thirty-day suspension,7 we hold that under Allen not only did petitioner prevail in this proceeding but he has also shown himself to be substantially innocent of the charges so as to be entitled to attorney fees. Those charges were all slight, and petitioner succeeded in cutting down the initial penalty of removal to a relatively short suspension. The Board will have to decide whether to allow full fees or to make some deduction for the fact that these minor and technical charges were sustained. See Thomson, 772 F.2d at 882; Boese, at 391. If any deduction at all is made, it should, of course, be small in view of our holding and discussion in this opinion.
III.
We reverse the Board’s decision denying fees as not warranted in the interest of justice and remand the case for a determination of an appropriate award in accordance with this opinion.8
REVERSED AND REMANDED.
. Docket No. PH07528310109.
. Petitioner was reinstated on April 15, 1985, thirty-one months after his removal became effective.
. 5 U.S.C. § 7701(g)(1) provides:
[T]he Board, or an administrative law judge or other employee of the Board designated to hear a case, may require payment by the *749agency involved of reasonable attorney fees incurred by an employee or applicant for employment if the employee or applicant is the prevailing party and the Board, administrative law judge, or other employee (as the case may be) determines that payment by the agency is warranted in the interest of justice, including any case in which a prohibited personnel practice was engaged in by the agency or any case in which the agency’s action was clearly without merit.
. See Allen v. United States Postal Service, 2 MSPB 582, 593, 2 M.S.P.R. 420, 434 (1980).
. The Board properly held that petitioner was a prevailing party. Van Fossen obtained a very significant part of the relief sought; the penalty imposed upon him was reduced from a removal to a thirty-day suspension. See Sterner v. Department of the Army, 711 F.2d 1563, 1566-68 (Fed.Cir. 1983); Boese v. Department of the Air Force, 784 F.2d 388, 390 (Fed.Cir. 1986).
. Footnote 1 of Sims, 711 F.2d at 1578, states: Petitioner’s [original] removal [mitigated by the full Board] was for (1) fraudulently using a government purchase document to obtain an electrical switch box for his private use, and (2) misuse of government time by absenting himself from his work area during attempts to return the box. Sims apparently intended to take the switch box off the base but ultimately returned it before doing so.
In addition, we noted in Sims that the removal was mitigated to a 10-day suspension based upon the retroactive application of Douglas v. Veterans Administration, 5 MSPB 313, 5 M.S. P.R. 280 (1981), and that the agency neither knew nor should have known — in the year when the adverse action was initiated against Sims — either the substance of Douglas or "that it would be applied retroactively to [Sims’] case.” Sims, 711 F.2d at 1582.
. As Sterner declared, "the extent of a party’s victory is clearly relevant generally to the justice of his cause” as is "the magnitude of the injustice done the employee.” 711 F.2d at 1567-68.
. Hopkins v. Merit Systems Protection Board, 725 F.2d 1368, 1371-72 (Fed.Cir. 1984), and Peterson v. Department of Energy, 737 F.2d 1021 (Fed.Cir. 1984), cert. denied, — U.S.-, 105 S.Ct. 960, 83 L.Ed.2d 966 (1985), mandate that, in fee cases, the MSPB be the respondent in this court even though the agency (here, HUD) which is not a party to this appeal is responsible for paying any award of attorney fees. It was suggested to us by petitioner’s counsel that it is difficult, if not impossible, to enter into realistic settlement negotiations with the agency (on the issue of a fee award) while the MSPB remains the sole respondent in this court, and that the MSPB has other concerns which inhibit settlement. It may be that agencies should intervene in fee appeals to this court or that both the MSPB and the agency should be respondents in those appeals, or that the rule of Hopkins-Peterson should be changed.