Many scholars in the judicial politics world do not know this, so I thought I would make a quick note. During a paper I prepared for the 2006 Midwest meeting, I discovered something interesting: Segal/Cover scores on a few occasions actually generate statistically-insignificant parameter estimates for specific years of voting. Newspaper reputation is a statistically insignificant predictor for every civil liberties vote cast by justices in the years of 1950, 1954, 1964, and 1992 (95% confidence interval and a two tailed test). The p-values are also greater than .01 for the years 1949, 1951, 1952, 1953, 1965, 1968, 1991 and 1993. The table below summarizes the results. The data comes from the Ulmer Project. It is a combination of Vinson Court and updated Supreme-Court data combined into a single, justice-centered data set using stata commands (available through Paul Collins and also the Law and Courts Newsletter).
What would attitudinal modelers make of this? Would they say that judging was so good in 1992 that no vote was influenced by justice ideology? Was that a special, vintage year or something? Better than the '69 Mets?
P-values for Segal/Cover Scores above .01 (civil liberties):
* The original version contained a spelling error in the title and a typo on the table. Both are corrected.