We further note that the plaintiffs have not included a copy of the trial transcript in the appellate record, so we are unable to determine whether the plaintiffs made an offer of proof at trial regarding why they wanted to offer board members' testimony. See Butts v. Freedman, 96 Mass. App. Ct. 827, 832 n.8 (2020) (appellant has obligation to include in appellate record parts of transcript necessary for review of issues raised on appeal). On this record, there is no basis for us to conclude that the Superior Court judge abused his discretion in precluding the plaintiffs from offering board members' testimony.