Segal–Cover score

A Segal–Cover score is an attempt to measure the "perceived qualifications and ideology" of nominees to the United States Supreme Court. The scores are created by analyzing pre-confirmation newspaper editorials regarding the nominations from The New York Times, Washington Post, Chicago Tribune, Los Angeles Times, St. Louis Post-Dispatch, and The Wall Street Journal. Each nominee receives two scores that range from 0 to 1 based on the average score of all articles from these sources:Qualifications: 0 means unqualified and 1 means extremely qualified

* Qualification scores are based on the characterization of each editorial as positive, neutral, or negative toward the nominee. Positive articles are coded as 1, neutral articles as 0.5, and negative articles as 0.Ideology: 0 means most conservative, and 1 means most liberal.
* Ideology scores are based on each editorial's characterization of the nominee as liberal, moderate, conservative, or not applicable. Articles characterizing the nominee as liberal are coded as 1, moderate as.5, conservative as 0; articles deemed not applicable are omitted from the ideology score.

The Segal–Cover scoring was introduced by Jeffrey Segal and Albert Cover in their 1989 article "Ideological Values and the Votes of U.S. Supreme Court Justices". The scores have since been updated as part of The Supreme Court Justices Database, a project led by USC Gould School of Law Professor Lee Epstein. The updated scores cover all nominees from Hugo Black in 1937 to Amy Coney Barrett in 2022. A score for Kentanji Brown Jackson has not yet been published.
Because the scores are based on perceptions before the nominee takes a seat on the Court, they provide a measure of the ideological values of Supreme Court justices that is independent of the votes they later cast.

Scores

The Segal–Cover perceived qualifications and ideology scores for all nominees to the Court between 1937 and 2022:

Nom. Order	Nominee	Chief Justice	Senate Vote	Ideology Score	Qualifications Score	Nominator	Year
1			67 – 18	0.875	0.160	Franklin D. Roosevelt	1937
2			Voice Vote	0.725	0.875	Franklin D. Roosevelt	1938
3			Voice Vote	0.665	0.965	Franklin D. Roosevelt	1939
4			62 – 4	0.730	0.820	Franklin D. Roosevelt	1939
5			Voice Vote	1.000	0.650	Franklin D. Roosevelt	1940
6		CJ	Voice Vote	0.300	1.000	Franklin D. Roosevelt	1941
7			Voice Vote	0.330	0.800	Franklin D. Roosevelt	1941
8			Voice Vote	1.000	0.915	Franklin D. Roosevelt	1941
9			Voice Vote	1.000	1.000	Franklin D. Roosevelt	1943
10			Voice Vote	0.280	0.930	Harry S. Truman	1945
11		CJ	Voice Vote	0.750	0.785	Harry S. Truman	1946
12			73 – 8	0.500	0.125	Harry S. Truman	1949
13			48 – 16	0.720	0.355	Harry S. Truman	1949
14		CJ	Voice Vote	0.750	0.855	Dwight D. Eisenhower	1953
15			71 – 11	0.875	0.750	Dwight D. Eisenhower	1955
16			Voice Vote	1.000	1.000	Dwight D. Eisenhower	1956
17			Voice Vote	0.500	1.000	Dwight D. Eisenhower	1957
18			70 – 17	0.750	1.000	Dwight D. Eisenhower	1958
19			Voice Vote	0.500	0.500	John F. Kennedy	1962
20			Voice Vote	0.750	0.915	Lyndon B. Johnson	1965
21			Voice Vote	1.000	1.000	Lyndon B. Johnson	1965
22			69 – 11	1.000	0.835	Lyndon B. Johnson	1967
23		CJ	45 – 43 *	0.845	0.635	Lyndon B. Johnson	1968
24		CJ	74 – 3	0.115	0.960	Richard M. Nixon	1969
25			45 – 55	0.160	0.335	Richard M. Nixon	1969
26			45 – 51	0.040	0.111	Richard M. Nixon	1969
27			94 – 0	0.115	0.970	Richard M. Nixon	1970
28			89 – 1	0.165	1.000	Richard M. Nixon	1972
29			68 – 26	0.045	0.885	Richard M. Nixon	1972
30			98 – 0	0.250	0.960	Gerald Ford	1975
31			99 – 0	0.415	1.000	Ronald Reagan	1981
32		CJ	65 – 33	0.045	0.400	Ronald Reagan	1986
33			98 – 0	0.000	1.000	Ronald Reagan	1986
34			42 – 58	0.095	0.790	Ronald Reagan	1987
35			Withdrawn	0.000	0.320	Ronald Reagan	1987
36			97 – 0	0.365	0.890	Ronald Reagan	1988
37			90 – 9	0.325	0.765	George H. W. Bush	1990
38			52 – 48	0.160	0.415	George H. W. Bush	1991
39			96 – 3	0.680	1.000	Bill Clinton	1993
40			87 – 9	0.475	0.545	Bill Clinton	1994
41		CJ	78 – 22	0.120	0.970	George W. Bush	2005
42			Withdrawn	0.270	0.360	George W. Bush	2005
43			58 – 42	0.100	0.810	George W. Bush	2006
44			68 – 31	0.780	0.810	Barack Obama	2009
45			63 – 37	0.730	0.730	Barack Obama	2010
46			Lapsed	0.730	1.000	Barack Obama	2016
47			54 – 45	0.110	0.930	Donald Trump	2017
48			50 – 48	0.070	0.400	Donald Trump	2018
49	Amy Coney Barrett		52 – 48	0.230	0.820	Donald Trump	2020
50	Ketanji Brown Jackson		53– 47	?	?	Joe Biden	2022

* The vote on Fortas for the Chief Justice position was on cloture and failed to receive the necessary two-thirds majority.

A highlighted row indicates that the Justice is currently serving on the Court.
A Senate vote in red text indicates that the nomination was blocked.
A question mark indicates that no Segal-Cover score is available for this Justice.

Predictive power

Segal and Cover found that their ideology score is strongly correlated with the subsequent votes of the justices in civil liberties cases, with a correlation of 0.80 and an r² of 0.64.
Segal-Cover scores require subjective assessment of subjective sources. They are not based on any observed voting behavior of judges.
In a 1995 paper revisiting the Segal-Cover score, Segal and his coauthors concluded that the ideology score was significantly more accurate for justices who served during and after the Warren Court. For earlier Court eras Segal et al. conclude that "scholars should be sensitive to changes in the legal, political, and social environments and use appropriate diagnostic tools to tease out their potential effects." They caution that researchers analyzing the ideology of earlier justices should supplement the ideology scores of earlier judges with "other potential determinants of the vote, or redefine their ideological variables to reflect as precisely as possible the issues that their Court addressed."