Political scientists Brian Calvin, Paul Collins, and Pamela Corley (at Univ. North Texas, Univ. of North Texas, and Vanderbilt, respectively) report results from their study that compares Supreme Court opinion text with text from the relevant lower court opinions. Over at the Conglomerate David Zaring's post provides helpful context. The paper's excerpted abstract, below, summarizes.
"... We argue that lower court opinions will influence the content of the Court’s opinions based on a number of factors, including the prestige of the lower court opinion author, the published or unpublished nature of the lower court opinion, the ideological compatibility of the lower court opinion vis-à-vis the Supreme Court’s decision, the type of lower court opinion, and the lower court from which the opinion emanated. Utilizing plagiarism detection software to compare lower federal court opinions with the majority opinions of the Supreme Court during the 2002-2004 terms, we uncover support for our hypotheses, indicating that the Supreme Court systematically incorporates language from the lower federal courts into its majority opinions."