In his book, Winning on Appeal, Ruggero Aldisert writes on the singular purpose of the appellate brief:
The only reason for your brief is to convince the appellate court to reverse or affirm. Forget about how you spotted and discussed all those issues on your law school exams. Forget about how you wrote that law review article setting a new world record for footnotes per paragraph. And forget the memo you wrote to the firm's senior partner outlining your brilliance with regard to some tiny corner of the law. You are not writing to get tenure on the law school faculty or to persuade the American Law Institute to accept your view in a new Restatement.
If you are the appellant, you know that the statistics are against you. You know how you have to beat the odds. In the United States courts of appeals, you want to be that one appeal in ten that reverses the trial court; or if it is a criminal appeal, it is that one case in seventeen.
As indicated in Aldisert's statistics, appellate advocacy on the appellant side is one of the most difficult tasks in the law. Consequently, it is well worth considering independent appellate counsel when prosecuting an appeal.