Government Code § 7927.500
CHAPTER 11. Preliminary Drafts and Similar Materials
Except as provided in Sections 7924.510, 7924.700, and 7929.610, this division does not require disclosure of any preliminary drafts, notes, or interagency or intraagency memoranda that are not retained by a public agency in the ordinary course of business, if the public interest in withholding those records clearly outweighs the public interest in disclosure.