Whether a court must review the merits of an omitted appellate issue before determining ineffective assistance of appellate counsel under Strickland

When a defendant claims ineffective assistance of appellate counsel for failing to pursue an issue on appeal and appellate counsel acknowledges that the issue was potentially strong but that he or she failed to raise it based upon a misunderstanding of the law, must the court review the merits of the omitted issue before determining whether appellate counsel performed deficiently under the first prong of Strickland for failing to raise the issue?