counsel at the third trial, in which he referred to BTM as having been found “guilty” of retaliation. The district court, however, gave a limiting instruction and cut short the plaintiffs opening statement. These curative actions effectively eliminated any prejudice.
VIII
The jury returned a general verdict of liability on Lilley’s claim of retaliatory discharge. Retaliation is prohibited under both the federal ADEA and Michigan’s Elliott-Larsen Act and Lilley brought claims under both statutes. However, the jury’s general verdict did not specify the statute under which it found BTM liable. The ADEA bars plaintiffs from recovering prejudgment interest while the Elliott-Larsen Act permits recovery of prejudgment interest from the date the complaint is filed. Mich.Comp.Laws § 600.6013 (providing prejudgment interest on all damage recoveries in civil actions); Brunson v. E & L Transport Co., 177 Mich.App. 95, 107, 441 N.W.2d 48 (1989) (applying prejudgment interest from date of complaint to date of recovery under Elliott-Larsen Act). The district court denied Lilley’s request for prejudgment interest.
BTM argues that the district court’s ruling on prejudgment interest was correct, citing Wojtkowski v. Cade, 725 F.2d 127 (1st Cir.1984) (plaintiff’s request for prejudgment interest denied because the court was unable to determine whether the basis for the jury’s award was state or federal law).
In contrast to Wojtkowski, the state and federal claims here are both for retaliatory discharge and involve substantially identical elements. Compare Wentz v. Maryland Casualty Co., 869 F.2d 1153, 1154-55 (8th Cir.1989) (elements of the ADEA), with Kocenda v. Detroit Edison Co., 139 Mich.App. 721, 726, 363 N.W.2d 20 (1984) (elements of Elliott-Larsen). Since it is not possible for a jury to find a retaliatory discharge under the ADEA without also finding retaliation under the Elliott-Larsen Act, the district court erred in denying prejudgment interest. See Bailey v. Container Corp. of America, 660 F.Supp. 1048 (S.D.Ohio 1986) (awarding prejudgment interest after general verdict finding age discrimination).
Finally, BTM contends that Lilley cannot receive both liquidated damages and prejudgment interest. The Supreme Court has held that under the Fair Labor Standards Act a plaintiff cannot recover both liquidated damages and prejudgment interest. Brooklyn Savings Bank v. O’Neil, 324 U.S. 697, 65 S.Ct. 895, 89 L.Ed. 1296 (1945). This circuit has applied that ruling to the ADEA; thus, a plaintiff cannot recover both liquidated damages and prejudgment interest under the ADEA. Rose v. National Cash Register Corp., 703 F.2d 225, 230 (6th Cir.1983). However, the prejudgment interest here is awarded under Michigan’s Elliott-Larsen Act while liquidated damages fall under the ADEA.
These awards are not duplicative. Under the ADEA, liquidated damages are punitive. Trans World Airlines, Inc. v. Thurston, 469 U.S. 111, 125, 105 S.Ct. 613, 623, 83 L.Ed.2d 523 (1985). Michigan holds prejudgment interest to be compensatory. Osinski v. Yowell, 135 Mich.App. 279, 354 N.W.2d 318 (1984); Foremost Life Ins. Co. v. Waters, 125 Mich.App. 799, 337 N.W.2d 29 (1983). Thus, Lilley may recover both.
IX
The Supreme Court has ruled that “the district court has discretion in determining the amount of a fee award.” Hensley v. Eckerhart, 461 U.S. 424, 437, 103 S.Ct. 1933, 1941, 76 L.Ed.2d 40 (1983). There is no precise formula for determining the amount of a fee award, but the district court is to be guided by the degree of success achieved through litigation. Id. at 436-37, 103 S.Ct. at 1941. The district court determined that Lilley achieved limited success at trial. We agree. While Lil-ley only succeeded in proving retaliatory discharge, this is sufficient to render him a “prevailing party” eligible to recover reasonable attorney’s fees, see id. at 433, 103 S.Ct. at 1939.