Fred Weber, Inc. (FWI) employee Kinserlow was injured when he fell from a workbridge. The workbridge no longer had any markings or labels, and it was unclear who had manufactured it. Kinserlow sued CMI Corporation, Bid-Well Division (Bid-Well). Bid-Well and another company, Gomaco, produced similar workbridges. FWI bought the workbridge before 1977 and paired it with a Bid-Well paving machine. Kinserlow asserted that Bid-Well (and not Gomaco) manufactured the workbridge from which he fell. To support that assertion, Kinserlow offered circumstantial evidence that: (1) paving machines and workbridges were typically kept together, (2) FWI had not purchased a Gomaco workbridge from the area’s exclusive distributor, and (3) Gomaco workbridges built after 1984 had metal triangles in the frame and no tapered-end sections, unlike the one from which he fell. However, Bid-Well offered evidence that: (1) Gomaco had sold workbridges with tapered-end sections since 1968, (2) Gomaco did not begin inserting metal triangles until 1984, and (3) Bid-Well had never produced workbridges with tapered-end sections. Bid-Well moved for judgment as a matter of law (JNOV) under Federal Rule of Civil Procedure (FRCP) 50(a). The district court concluded Kinserlow had not offered sufficient evidence for a reasonable jury to side with him that Bid-Well was the manufacturer of the workbridge from which he fell. The judge concluded the evidence favoring each party was about even. Thus, because Kinserlow bore the burden of production, the court granted JNOV for Bid-Well. Kinserlow appealed, arguing the district court improperly weighed the evidence and should not have considered Bid-Well’s unfavorable evidence.