What is the test for a jury to be found guilty of reversible misconduct?

Although defendant mentions a number of forms of alleged jury misconduct, he offers argument as to reversible misconduct only as to the jury's discussion of his prior record and its apparent concern with the length of deliberations. For failure to make a developed argument about other forms of alleged misconduct, defendant has waived any claim of error based on them. (See People v. Turner (1994) 8 Cal.4th 137, 214, fn. 19.) We therefore consider only whether defendant has shown prejudicial misconduct as to the points he argues.