theory at trial, and although the district court erred in admitting Sienkiewiez’s statement, the error was harmless. Wantuch makes the same arguments under Rule 701 regarding the admission of Robinson’s testimony. Because Wantuch failed to contemporaneously object (or state specific grounds for his objections) to any of Robinson’s testimony of which he now complains, we review Robinson’s testimony for plain error. See Fed.R.Evid. 103(a)(1); United States v. Swan, 486 F.3d 260, 263 (7th Cir.2007). Under plain error review, an error must be “clear or obvious” and “affect substantial rights” in order to warrant reversing the district court’s decision to admit the evidence. United States v. Schalk, 515 F.3d 768, 776 (7th Cir.2008) (citation omitted). We will not correct a Cir.2006) (<HOLDING>). Unlike Sienkiewicz’s testimony, Robinson did
holding that a participant in a conversation may testify as to his understanding of the conversation to satisfy rule 701as requirement that the testimony be rationally based on the witnesss perceptions holding that the appellant waived his claim on appeal because he failed to address that claim in either his application for a coa or his brief on appeal holding that a witness may testify about his subjective interpretation of a conversation in which he is participating as long as his opinion is rationally based on his perception and is helpful either to an understanding of his testimony or to the determination of a fact in issue holding that lay testimony as to the presence of asbestos in the workplace was admissible because it was rationally based upon the perception of the witness holding that the presence in the courtroom of an expert witness who does not testify to the facts of the case but rather gives his opinion based upon the testimony of others hardly seems suspect and will in most cases be beneficial for he will be more likely to base his expert opinion on a more accurate understanding of the testimony as it evolves before the jury